You'll have to look at the different makes. They range from sort of having to "jump" from the lower seat to the bed to some that sort of have steps. As a very general statement, usually the larger (meaning also heavier) TCs have more features such as easier access to the bed.
Another point about making the bed easier to access or use, is to pay attention to it's orientation. TCs with broadside beds going from one side of the TC to the other, are more of a PITA because they require one person so always be crawling over the other. Whereas, beds that run lengthwise, or are orientated from front to rear, don't have that inconvenience.
While going to a dealer to see the different types is always a great idea so that you can see how you'll fit it the TC and it's features, I'd also be looking on line at different brochures to see what other makes have that your dealer may not be carrying.
Bill