On my Fort Worth 1925 route, I'm using the donationware RWA Lakeside Route (don't know if I need that, since I'm also using RCAP) and the payware Bessemer & Lake Erie, because it's set in my era. Other than that, a ton of freeware scenery assets, same as my old Cimarron & Pacific route, especially jpetersjr and GreatNortherner.
I don't have a lot of payware, and thus I miss out on almost all routes, which generally use a lot of payware. If I have to buy a payware route in order to play a freeware route, I generally don't.
I'm guessing most active route builders and players, the kind who post on the forums here and elsewhere, have a lot of payware. I just can't afford to do that, so stick with freeware for the most part.