That's strange, here in Canada Toyota only sells the RAV4 with 4WD, but in the US all trims are available with 2WD as well. Sounds like you've got a plan, phone a few days ahead to see what they'll have kicking around. Being that it's a city location and you're reserving a "specialty" vehicle that doesn't get moved around often, they should be able to tell you a few days out. I'd also say it wouldn't hurt to call ahead now and see what they generally carry, and ask if they're all equipped with 4WD. I've done this before with other agencies with beneficial results.