I went down this very same road when I bought my Momentum 394M Toy Hauler. It had a King bed and on the curbside of the bed, there simply was not enough room to walk from the end of the bed up towards the head of the bed to get in....you basically had to crawl into bed from the end. In my case, with the Momentum, the King bed setup basically had an "extension" added onto the existing under bed storage area that gave it the width for the King. I went to work with a saw and removed that "extension" area, used some of the paneling and corner trim to dress it back up and look like it would have been if it had been a Queen bed setup. I also cut down the width of the plywood and redrilled the hinge holes to make the plywood centered on the "original" size base. Here's a couple of pics that I took during the process.
If you look at the very limited amount of space between the bed base and the curbside wall, it's almost non existent.....
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As you are looking at the right side of the bed, the side that is closest to the curbside wall, that small underbed compartment area was removed and the "original" size part of the base was left intact.....LOOK at the amount of space that was gained between the original base to wall vs. the modified base to wall area
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This next pic shows the bed plywood that the mattress lays on. If you look closely, you can see the holes where the bed struts were originally attached and how the plywood was moved over towards the closet side, in order to center the bed......
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This is the finish mod to cut down the bed and make more room. Like I said, go back and look at the floor and compare the amount of room between the original installation (base to wall) and the modified bed with much more base to wall space. As a finishing touch, we bought a flannel sheet to put on the plywood and then stapled it from underneath. It serves to keep the mattress from sliding around during travel.....
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Hope this helps a little. Oh, and rounding off the corners of the plywood probably really wasn't necessary, but I did it anyway.
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