We have fernos, so we just push it in. The landing gear retracts as it comes in. We generally run 3 man crews but even with two guys there is almost never a patient too heavy to get into the truck this way. The limiting step is usually getting the pt onto the cot. Most of them can stand to some degree so we support their weight and pivot them into the stretcher-chair. If they are too big and can't stand and are lying on the ground, we can put the stretcher all the way to the ground and kinda just roll them onto it or a backboard while we wait for our engine to get there to help.
I dislike the stryker power cots. They are good for IFT, but in the field, they are more trouble than they are worth. First you have to support the weight while the landing gear retracts. Second, in the field, they can't go to chair mode so pivitoting someone is out of the question. Third, when all the way down, they are still about 6-9 inches off the ground so someone on the ground still needs to be lifted that high. And 4th, when you are in rough terrain, you gotta pick up the cot, and with all of that gear on it it adds at elast 75 lbs if not more.