2 cats would probably be a good idea--and if you can find an already bonded pair up for adoption, it would eliminate the stress of having to introduce them. We adopted a 2nd stray about 3 years after we took in our first stray and slowly introduced them--took about 4 months before we were totally comfortable leaving them unsupervised together, but now they're such good friends.... So adopting a non-bonded pair can also work if you have the time to spend and a way to keep them separated until they get friendly with each other.
As for the time away, I know of a lot of people who just have neighbors check in on the cats a few times a day when they're on a trip. Cats like being in familiar surroundings, so leaving them home is often the least stressful thing for them. If you trust your neighbors, it sounds like the perfect solution, and shouldn't be too hard on your cats. If possible, you can practice--take a short, over nite trip and have your neighbor come in for the kitties just to see how it goes. If it goes well, leaving them probably won't be a problem. And there's always the option to board your kitties when you're gone if the home visitation thing doesn't seem to be working
How exciting! I hope you share some pictures with us when you adopt your kitty or kitties!
