Need advice on what to do about a stray cat and if it is a ok to keep her indoors

Hello i am new to the site and looking for any help or advice that anyone may be able to give. I have read through a few other threads about people taking in strays and seen some useful suggestions about what steps to take in trying to settle a stray cat indoors, but i am really needing advice on what people think is the best way forward. I am unsure what is for the best, and worry so much that i may make the wrong decision. Sorry if this post is a little long, i just want to set out the situation clearly. 

For the past few months we have seen what we believe is a stray cat which lives in the garden next door to us, she seems to sleep under a covered area where we have seen her often coming out of and running to on many occasions and she is certainly not the neighbours cat.  I have a few times tried to encourage her with a bit of food, but she has always been so nervous it never would approach and always ran away. 

Just over a week ago that all changed. For some reason when i saw the cat this time i tried a lot harder to reassure her and get her to have some food in a dish outside. She did and in a matter of days we have made a lot of progress with her coming inside to eat some dry cat food from a dish several times a day,  She has let me feed her by hand, i can encourage her sometimes to come up close and she has explored parts of the house. She has even been upstairs several times, and laid on a bed (with some encouragement) and had a short sleep.  She has even sat on the window ledge outside one morning waiting for us to open the door for her to come in and eat. . I think she trusts me and is now used to me already. 

The trouble is she is still very nervous, if im in the room at the time she comes inside she is fine and often comes over to me and lets me stroke her. But  if i come round the corner after she has come in, she will often run out and hide under the area we believe she lives. Most of the time she is in the house for just a few minutes before running back out, especially when there is a noise like the phone, door, or someone else moving about in the house. One time she came in and went to sleep upstairs for about an hour i had shut the backdoor, when she came down and saw it was shut she freaked out initially, but i quickly opened the door and she was ok and came back a few hours later.  

My question is what should i do next? I have already become very attached to the cat and ive bought her quite a few things in recent days such as a cat bed etc. One day a couple of days ago she did not come in at all and i was very worried, she came back the next day but i know that if im so worried after just a week of getting to know her,  im going to be a nervous wreck if she did not come back for a longer period of time or something happened months down the line. 

I think i want to keep her indoors permanently, i understand it will be difficult initially as she has spent months outside on her own and so is use to it. But i believe that it would be safer for her (and best for everyone) if she stayed inside, especially as im almost always in the house so she would not be left alone. But my husband does not think it is the right thing to do, he is very much of the view that cats should not be kept inside, and that they need to be able to come and go. So he thinks we should just carry on as things are.  I can really push the issue and convince him its for the best, but i need to be sure before i do that. Whilst i strongly favour keeping her in, im not sure if its the best for the cat or if im just being selfish by wanting to keep her inside.  Whilst we have made great progress, if we just carried on as things are i dont think we would make much more progress (as she is too use to going to the same outside hiding/sleeping place). 

The best way forward i think is to try keeping her in over a few days, if during that time she is clearly unhappy and not getting use to it, id let her back out and hope she still comes back to us. I think (maybe wishful thinking) that after the initial shock i could calm her down and shed settle, then at some point in the next few weeks wed be able to take her to the vets to get her checked over. If we do decide to keep her indoors, the other issue is we did also see cat leads are available so we could take her out into the garden regularly (but again im unsure if that is a good idea as it may keep reminding her about being able to go outside when we want to get her use to just being inside).  

Sorry again for the long post, any suggestions and advice would be very helpful and much appreciated. Thanks

No matter what you decide about keeping her inside, you must have her vet checked first thing. If she needs to be spayed, have that done ASAP. First of all, she's been on her own for awhile, so she is either pregnant or in danger of becoming pregnant. That needs to be addressed now. Cats are far better off inside only. It's safer and they live longer.

If for whatever reason you decide to let her out (after spaying her), is there a porch you can enclose so she gets the outside experience without the outside troubles?

Thank you for helping her. She is a lucky kitty to have found you!

Also remember that she will need time and you will need patience as she adjusts to her new situation. If you can, give her her own space - a room with a bed, her litter box and food and at least one hiding place (a cardboard box is ideal). If the room has a bed, block under the bed. Talk sweetly to her, never rush or push her and move slowly when in her space. She will eventually realize you mean her no harm

Harp music played low and a product called Feliway (a plug-in with cat pheronomes) will also ease the transition.

Im seconding Ondines advices.

She probably is already fixed or is sterile, Otherwise she  would prob by visibly preg by know. But best to get this checked out...

Good luck!

I wanted to reply to give you a little encouragement.  I have a cat that started out much like yours.  He showed up as a kitten at the neighbors' garage (we fed some ferals there and she let them stay in her garage) and I started to work on getting him to trust me so I could get him neutered.  It took months to develop trust and then I finally caught him and got him neutered and had to keep him inside overnight.  He was not fond of the inside thing but thereafter he would come in for bits of time and check things out.  After a few months of that, I sold my house and moved to another town and made the decision to take him with me.  Initially he was shut in a basement room with his friend (the neighbor's cat that he abandoned and I took with me as well) and he absolutely was beside himself.  He meowed, tried throwing himself at the window (which was high up and nearly unreachable but he managed) and seemed miserable.  After two days, I let him out of the room and there was still much meowing and distress.  After about two weeks that started to even out and now, after three months, he is a very good (other than digging in plants lol) indoor cat.  I have not let him out at all except once accidentally when my backdoor blew open in the early morning and I didn't know it.  He came back from his little adventure outside somewhat traumatized and has not asked to go outside again.