Although quite a lot of time has passed and the OP showing up here was already 7 years ago. But in other forums, I was taught to be sparing with threads and so I’m recycling here.
We also have two indoor cats, and we’re afraid they wouldn’t really cope with proper outdoor access. One is an old Thai cat and very trusting. She would either get stolen or follow us and our kids on the way to work and school and then get run over on the main road. The other is so skittish that she would probably run away at the first unfamiliar noise and climb some tree. She is so clumsy that she would then fall down and break something.
Therefore, we are already thinking now (probably about a year before moving) about how we can either make our garden reasonably cat-safe (going out and coming in) in a cost-effective way or set up an enclosure that is not too ugly but still practical.
Fencing or netting off the terrace has the big disadvantage that it is impractical because we want to use the garden regularly. Then you would also have to install some kind of door there.
A separate enclosure is annoying because you would then have to regularly carry/lead the cats there or build a corridor to it.
How does the forum community see this? Have you had a similar problem? Did you just take your chances? Or did you spend serious money and made the whole property secure?
Many greetings
Tolentino