I don't recall any comprehensive solutions being posted. Use the word 'wheelchair' in the search function. Any returned thread will have the search word highlighted in red somewhere in the thread. Member 'nevisstudio' has been working at this issue.
Airstream tends to make custom trailers to business proposals only. The NPR Story Corps trailer is an example and has a wide door and ramp, but this trailer is pretty short and would not have space for what you're asking. It has no LP tanks.
No frame members can be removed. Both the inner and outer skins are structural, providing shell rigidity and diagonal bracing. Understand the specifics of capacity of trailers before you decide on what gear to add inboard. See:
http://www.airstream.com/product_lin...#trailerweight. The difference between 'Dry Weight' and GVWR is the useful load you can plan on the structure bearing. You are talking wheelchair lift, but this limit includes food, clothing, and other necessary aftermarket gear you need for hitching or setting up the trailer.
If you wish to find more posts by a member, click on their screen name at the left of any post and you can "find more posts by" that member.
I expect accessibility from public facilities such as state parks. I've seen accessible toilets in many campgrounds. Showers tend not to be wide and there is some inconsistency in curbs or floor heights. The occasional park shower setup would present little in the way of barriers -- but this is inconsistent in my opinion and not by specific design. I was at Wisconsin's Blue Mound S.P. just a week ago and they have a reservable small accessible cabin in their RV campground loop -- an exception by far! Anybody have more locations like this?
Welcome to the Forums littlebear89! There is much to find on most any topic -- and very few topics that are not relevant to each person pulling or maintaining an Airstream. Best wishes, and I hope you find a way for both of you to get outdoors in this fashion!