The last two times I was out of town (for about a week each time), I had a friend who LOVES animals pet-sit. (She volunteers at a horse sanctuary, because at any other sort of animal shelter she would want to bring all of the animals home.) I had her come over to the house one evening a few days before I left, to introduce her to the kitties. They both got along well with her and were just fine when I got back! (The litter boxes were a bit full, but that's another issue.)

Perhaps if your pet-sitter was willing to come around and meet your kitties, you can assess how they react to her/him and determine whether you can have her check on them. Otherwise, if it's only two nights they might be all right with a supply of dry food and a substantial water fountain.

Liz