Very good question and one I too struggled with at first at my old house with sliding glass doors. I ended up cutting filler strips of hardwood Oak that were just a little higher then highest ridge on the track. This includes one strip in front of the inside ridge. Then use a few more boards at different thickness to taper off like a ramp. Same as what @ryan1234. You can buy them in different thickness and sizes at just about any hardware store. Then have a piece of plate steel I heated and bent go on top of this. You don't want to make it just enough to make a speed bump. You want to stretch it out to about 1.5 feet on both sides. It's a bit of work but once you are done you will always have it. I have a large collection and went through a lot of games so was worth taking the time to make it right. PS I also move my games by myself so easier the better. At my new house I have an regular entrance door. Ending up just cementing a small ramp in front of the door. Forgot to say I also cut the wall out to put in a 36" door. The 32" door was too narrow.
Another way would be to build a cart with inflated wheels to go under your pinball lift. The inflated wheels go over stuff better then the hard wheels on the lift does.