Will this work for framing?

Well I'm on about my 20th revision and have come to this profile. (A familiar shape.)
This is some of the cutaway details.
A close up of the front radius.
The gray is the frame. Should I worry about cutting it down to 72"?
Red is the 2" floor frame. 86" long.
Black is the floor. 90" long.
White is the mattress. 75"long.
Blue is a piece I'll cut out of plywood to tie everything together
(I plan on making 3 of the plywood pieces. 1 for each side and one to run down the middle. I'll tie all 3 together with spars)
Green is the roof insulation.
That's the solution I came up with for the bottom radius' but if anyone has a better or easier way I'd love to hear about it. All input is welcomed.
Thanks,
HF ALERT! The 20% off coupon is back.
http://ww2.harborfreightusa.com/showpage_retail.taf?pageid=214&email=
This is some of the cutaway details.
A close up of the front radius.
The gray is the frame. Should I worry about cutting it down to 72"?
Red is the 2" floor frame. 86" long.
Black is the floor. 90" long.
White is the mattress. 75"long.
Blue is a piece I'll cut out of plywood to tie everything together
(I plan on making 3 of the plywood pieces. 1 for each side and one to run down the middle. I'll tie all 3 together with spars)
Green is the roof insulation.
That's the solution I came up with for the bottom radius' but if anyone has a better or easier way I'd love to hear about it. All input is welcomed.
Thanks,
HF ALERT! The 20% off coupon is back.
http://ww2.harborfreightusa.com/showpage_retail.taf?pageid=214&email=