The advice here has been great. A few comments back:
1. Camping. I love to camp, but when I have my hubby. After driving 500+ miles a day with my kids and the dog, the last thing I want to do is set up a tent, cook, deal with lanterns, and sleep on an air mattress. I want a hot shower, a bathroom, and dinner already cooking perhaps in the kitchen. I also RV'd when I was a kid and playing games in the back, chilling out (now with TVs - not then!), hanging on the bed with the dog... sounds like so much fun and the boys are super excited about it.
2. I'm not too concerned with breaking camp as I think once we "plug in" we will stay nearby. My sister had two RVs and I traveled with her in her smaller class C years ago which she lived in with her hubby and dog, and it didn't take long. Granted, she was a pro! That said, we're bringing bikes so unless we're driving to the grocery store, I think we'll stay at the camp when we set up. We also don't plan to camp in one spot for more than 2-3 nights, most times it will be one night. Plus when we are with family, we'll probably sleep in the camper.
3. I've thought about towing a pop-up but it's not what we envision for the trip. Since this is a big deal for us, I really want to do it right - as we've dreamed out - if we can swing it (time & money)
4. Smaller is I think the way to go. The boys won't be thrilled sharing the overhead bunk but they'll get by ;-) They can always choose to camp out on the floor. DH will only be with us for 10 days too, so that's a consideration. I'll be more comfy driving a smaller RV.
5. In terms of cost, I have the cash and wouldn't finance. Partly because of the hassle and additional cost, partly because of the risk (I'm an accounting and tax professor), and partly because I try not to finance depreciating assets. It was my brilliant sister's idea, but she has no issue with debt or risk. Let's just say we don't see eye-to-eye on a lot of things.
6. I'm thinking if I can't rent from an individual locally, I will probably purchase a used 26' or so, aiming around $15k though my hubby will freak I think.
7. I like the idea of an earlier trip - spring break! Also I have the month of May off so that may work better. We have family near DC and could park and ride the metro in.
Thanks all - please keep the thoughts & ideas & suggestions coming! Latest route:
CT
Niagara Falls (1 night) - camp
Northern Indiana (1 night) - friends
Chicago (a few nights - hotel, leave RV with family in Evanston)
Milwaukee, Madison, and Wisconsin Dells :-) (1 night) - camp near the Dells
Minneapolis (2-3 nights) - friends - pick up hubby from airport
Bad Lands, ND (2 nights) - camping
Mount Rushmore - visit and not stay
Grand County, CO (several nights) - family
Denver (airport - drop off hubby), Boulder (1 night) - family
Arches Nat'l Park (1-2 nights) - camping
Zion Nat'l Park on way to camp somewhere on way to Grand Canyon
Grand Canyon (2 nights) - camping
Camping & driving across NV, AZ, TX, AR, OK (? nights)
Nashville (1-2 nights) - camping
In and out of the Smoky Mountains, various potential detours, camping & driving up north (? nights)
Annapolis MD (2-3 nights) - in house with family. Ditch RV and train into DC
Drive back to northern CT (1 day driving)
Roughly 31-34 days depending on detours, at 400 mi a day (more when we zip across the southwest)