Try one of JD Simpson's womens rides out of bikeworld. Start with that, and work up to a wheelmen ride. All wheelmen rides have loops of varying distance and maps. You might also like the Hill Country Bicycle Touring Club, their rides tend to be slower paced than Wheelmen rides, and I think they have no drop rides. The wheelmen also run a rider education series, where you can progress with a group to longer distances, all no-drop. The more I think about it, the latter may be the best way for you to progress.