Sounds to me like you're gonna need a tow-behind yard vac of some sort, or a riding mower with a bagger attachment. I've been looking to see what's available for SCUT's for a long time because I want to aggregate all my yard tools to fewer engines and more pins to connect them to a larger more useful machine.
DR makes a really nice vac, but even that is too small for my yard. It has to be able to eliminate the constant stop/empty/restart operations that slow down cleaning up my yard. Then again, what I do now (bagger on my riding mower) is a lot better than a rake and a wheel barrow. I wanna say that Swisher also has a good machine, but both tend to be a little pricey. Could be mistaken about Swisher, though. Either is pricey, but good quality.