Well, things seem to be progressing slowly. I've managed to glue up one side of the trailer so far, minus door. I spent a lot of time researching and planning (and removing snow/ice), and not enough time implementing the plan. I have recently move to the implementation phase of the camper. I have managed to accumulate a lot of the material that I will eventually need, and it is stored all around my basement as my actual work area to assemble this thing is about just about camper floor (5x8.7 feet) plus 3 feet (8x12), and along one side I have to store plywood and insulation. On hand I have a queen size memory foam mattress, fenders, windows, shocks, lights, powered cabin vent, door hinges, hurricane hinge, switches, extension cord with built-in 15 amp breaker, timer for ceiling fan/heater, battery condition indicator, fans, battery charger/converter, drawer slides, butyl tape, 100 lb gas galley struts, trailer break-away kit, and misc. stuff. I've spend right around $3400 so far, and am about $600 under budget for where I thought I would spend so far. I figure I have less than an additional $1000 to spend at this point.
I've also managed to make a "fan bar" for across the pillow area. It has 2 low powered fans for each side to create a "spring breeze" so I won't feel quite so claustrophobic, and a more powerful one in the middle of each low powered for when we want a more serious breeze (controlled by 2 switches for each side). Also in the bar is our central inside power control panel, with switches for fans, dome vent, dome light, heater/vent selector, mechanical timer, power source selector, main cabin power, and battery condition indicator. The "power source selector" is just a switch to decide if I want "continuos power" to route to the heater/vent, or if I want to route the power through a mechanical timer so I can set it for any time up to one hour with auto shut-off. The "heater/vent selector" decides if I route the continuos power/timer power to the vent fan OR the heater, since I will never want to use both at the same time, and that way I can share the timer between the heater or the vent, depending on conditions. I like the idea that if I wake up in the middle of the night, hot or cold, I can select the vent or heater, set for 10 minutes or so, and fall back asleep and know the device will turn itself off automatically.
I got the trailer registered last week, and it was easier than I thought. No inspection, and I was in and out of the MA Registry in under 5 minutes. I'm taking it to the welders next week to get the trailer tongue lowered by 10 inches, and to get shocks supports manufactured in and welded in. Welder says less than $200 total for both.
You can see in the picture how cramped my work area is, and a red flannel shirt wrapped around a wood support that I manage to bang my head on it at least once every time I am down there. I am only 5'9" but the wood support hangs at 5'6". I never really see it coming until the side of my head makes contact. The camper floor is only screwed together right now with no glue because it has to come apart to get out the bulkhead doors! I am thankful for what little space I have as it lets me get a jump on the camper before spring gets here...but I really wish I had more space so I could walk all the way around the camper floor without having to step up on it to get by something.
I have a lot of wood at the back end to stiffen the camper sides at the galley end, and to give places to screw into solid wood for the galley and cabin cabinets. I have no doubt that there is much more wood than I need, but it will help offset the weight of the battery on the end of the trailer tongue. There is more wood inside the walls because the plywood I have for the inside is really light, actually it reminds me of balsa wood. It may be just under 1/4 inch, but it weights less than half what the marine grade 1/4 inch weighs. I got it at Home Depot and I think structurally I like the idea of the extra 3/4 inch pine with the marine grade ply.
I'll check back in after I make more progress.

*When doing anything, if there exists no possibility of failure, then any feeling of success is diminished.
**The glass is neither half full nor half empty...it is simply twice as big as it needs to be.
***If at first you don't succeed, redefine success.
****When I die, I want to die like my grandfather, who died peacefully in his sleep. Not screaming like all the passengers in his car.