Use two different approaches. The first yard I dealt with has three travel lifts and two self-propelled hydraulic yard trailers. They haul boats with the travel lifts and put them on the yard trailers (except for boats over 50') to move them around the yard. That works very well and they can pack the boats into the storage buildings and yard very tightly.
The yard I deal with now has a Brownell hydraulic trailer towed by a normal semi-tractor. They are inland, so they use the Brownell trailer to haul boats at the local boat ramp. The trailer is also used to move boats and put them into storage sheds or the outdoor yard. The tractor trailer setup needs more space for maneuvering than a self-propelled hydraulic trailer which means rows of boats outside are farther apart. They do save money by using only one piece of equipment. The tractor-trailer setup can haul boats up to about 50'.
For your situation I think a self propelled trailer would work very well. They need a minimum of space to maneuver and can pack boats in tight if the operator knows what he/she is doing.