Newbie in Virginia looking to get building

[dstydream]

Hi everyone. My name is Amy and I live in the Shenandoah Valley in Virginia. I love living here in the mountains and we have a really great state park pretty close to our house with two lakes and a lot of camp sites and even a beach.
I have a 17 year old son that is disabled (he has a trach and a vent) and cannot stay in a typical teardrop with my fiance and I but can't say completely by himself either. My other son actually wants to stay in a tent by himself so we have him covered. I have found a great design for one and I found another one that has a tilt out little bed for my son (he is only 5 foot and weighs about 90 pounds). But it is a taller one and I am afraid of the weight of it being too heavy for my minivan. I have a 2007 Chrysler Town and Country Touring van. I have put pictures of the one that I really like that I have the plans for but it is a 5 x 10 and I was thinking more along the lines of the 4 x 8 trailer kit from Harbor Freight to build on. I have seen a video on YouTube where someone built a wooden frame to add onto their 4 x 8 and actually made a 6 x 10 and I only want 5 x 10. Is that something that is safe to do? If this would be safe and not too heavy, I would love to do this for our family and then have storage under our bed. But the "Simple" plan is just what I would want if I can figure out a way to get my son in it too.
Any suggestions would be greatly appreciated.
This is where I have found the plans that I really like... but would need the 5 x 10 trailer.
http://www.ebay.com/itm/TEARDROP-Camper-Trailer-Tear-Drop-RV-Camp-PLANS-2-/181282249111?pt=LH_DefaultDomain_0&hash=item2a35439997


Link for the camper with the tilt out bed I would like to build in minehttps://www.youtube.com/watch?v=ExZSpJ97h68

Link for the camper that put on an extra wooden frame to make the trailer bigger https://www.youtube.com/watch?v=lT8JGdkkfAU

[citylights]

Check design resources on this website and design library. There are plans on this site exactly like the one you linked... For free. Also check the hall of fame for a bunch of pictures to examples with links to build journals.

[Glenn Butcher]

I posted a reply to you in the Ladybug-Out build thread, but reading here, it's now clear to me you'd need a bigger camper than you'd get on the 40x48 trailer. Northern Tool has a 5x8 trailer that might be worth considering; making the floor to fit the frame is more straightforward.

[dstydream]

If I can't sell my little trailer then I can't really afford to get another one right now. I have found another teardrop that does not have a galley in the back and they back it up to a 10 x 10 tent that goes under a straight leg canopy. I don't mind sleeping in that tent (we already have one of them). We even have room for Jamie in there. But there are some places that we want to go that will not allow a generator if you are only in a tent and they only give the sites with electric to the people with a pull behind camper of any kind. This is even true for some of the campground areas at the race tracks that I want to take my son to.

If I make a small teardrop type camper on my small trailer and back it up to the canopy tent that we already have my fiancee and I can sleep on our air mattress in there and Jamie can be inside the camper with his ventilator and be more protected in there but we will still be all together so that I don't have to worry about not hearing him if were to stop breathing at night. This will satisfy those campgrounds that won't allow us to have electricity for my son unless we have a camper that pulls behind our vehicle and we can still all be together and the very expensive vent will be protected from the weather.

Here is a picture of what I am talking about.. http://i236.photobucket.com/albums/ff221/dstydream/1_zps087664a5.png

thank you. I just love looking at this site, the plans and all of the pictures and stories. It is an awesome forum.
Amy