The term "difficult to shift into reverse" can mean different things. You may have a variety of problems here. The clutch and/or adjustment is only one of them. The clutch adjustment is on a rod connected to the pedal. It's most likely behind a panel and I can't tell you how to access it on your model. Sometimes there is a plastic pop out cover you can pry out to expose it. That is the pedal free play adjustment. It really shouldn't affect shifting into any one range or gear so that's probably not the problem. The pedal has a return spring that holds it up against a stop. If you can depress the pedal against that spring an inch or so with two fingers before it becomes too hard to push then the free play should be okay.
It has a cable in the shuttle shift mechanism that could be part of the problem. Most of that is probably also hidden so you will need to search for it. It appears there may be a threaded yoke on the transmission end of that cable that could be adjusted to affect the amount of travel involved with rotating the shaft going into the transmission. The cable attaches to mounting and support brackets on each end. The clamps or whatever secures them can work loose and cause that sort of problem.
There is also a synchronizer and shift fork inside the transmission that can be a factor here as well. Not much you can do from the outside to affect that.
