Need Advice, Proper Care for Indoor/Outdoor Cat
Hi all! Experienced cat owner, but have always adopted kittens and raised them solely as indoor cats. We recently, quite accidentally, adopted a 5-6 month old stray who unexpectedly approached when offered food after less than 5 minutes of coaxing. (Offering her food was something I viewed as a game with the kids...I never thought she would take it!) After taking her in the house, she "tamed up" in a matter of hours. In many ways, she is more friendly than the 12 yr old cat we raised from a kitten. Despite the friendlyness, she was definitely a stray cat when we met, as she was skin and bones and so hungry she drew meaningful blood eating from my hand. Its possible she might have been a housecat at some point -- I'm not sure the quick friendly behavior is consistent with a 5-6 month old true feral cat -- but it clearly wasnt recent given her state.
Anyway, we have a 12 year old cat that is relatively unaggressive, but will hiss at new cats. We have tried and failed to introduce her to another cat in the past (mother in law got sick and we took her cat for a while). So we arent real eager to try another introduction, and more importantly, the former stray wasnt taking to the literbox real well and was peeing inappropriately. It could be just a matter of being more patient, but we are afraid to be patient, because in the remote past the existing cat would pee whenever it smelled a place other cats had done so. We tried to get a taker for her, but could not, and now I'm not sure the family would be real happy with giving her away. So we made her an indoor/outdoor cat; our existing cat spends time in the furnished basement when she is in. She doesnt pee inside at all even if she is in for hours. She is getting spayed tomorrow.
Here is the thing: she doesnt mind going out when its nice, but HATES going outside when its raining (which it has been a lot lately) and will even growl and hiss at me, and we arent at all sure what happens in wintertime. We live in New Jersey, and winters do involve some snow and sub-freezing temperatures. She doesnt seem to wander far, and I'm not overly worried about cars or dangerous wildlife, more so the cold/rain. Even if its not dangerous for her, I'm worried that it will always be a battle to get her to go out in winter.
We have a screened in "Sun" room that would at least put a roof over her head, but driving rain will get in to some minimal extent, and in winter it will be as cold as the outside.
How do I set up for her? What type of "cat door" can I put in the screen door to the sun room (can I just buy a door with one built in, not that handy), and what type of arrangement will best offer her some shelter from the cold (presumably in the sun room, but open to other ideas).
Thanks for any suggestions!