thanks everyone for the feedback and consultation!!
all good questions and thoughts!
the trailer will (in current design) be cut down to 6' so that the axle is further back as recommended frequently.
the floor and camper structure will extend a bit beyond that in both front and back (essentially the length of the lower curve front and back), which means ill still have about a 6'2" mattress.
We spent the last year driving around mexico and central america in a homemade camper and i designed that mattress right at 6'...decided to give myself a few extra inches for this one (the width of our last one was also significantly narrower than 4' for us and the dog...so this should feel PLUSH!!
Started to dismantle the trailer yesterday and will try getting it cut down today.
I had seen a post or two about a "stripped down" HF trailer...is there something else i can do to remove weight (short of the full blow ultralight trailer...which i wish i would have seen before buying)?
Regarding hatch...i had placed this question in the design thread but didnt get much feedback. Ive never seen this done, but plan on mocking up a little test hatch to see if it works.
rather than either option above, id like to think a "bifold" hatch is possible that swings up and out with a second hurricane hinge for more shade/rain coverage. anybody seen or tried this??

keep the ideas coming and thanks for supporting the newbie!!
