Unfortunately, I may have to spray just a wee bit of cold water here.  From my thinking, if you are going to deal with Craig's List, make sure to have an extra person or two when you do the meeting with ANY potential buyers.  I don't like the service at all because I hear of too many incidents where the potential buyers are actually criminals looking for a score.  (Remember that Jo and I work for a law enforcement agency, so we have a tendency to be very cautious about such things.)  When Jo sold some of our furniture from our RV and out house, she used Craig's List.  But, we had a small-town address and most interested buyers were from small towns here in Oklahoma, so our "clientele" are a totally different sort than city-dwellers.

I have absolutely no knowledge of your business, but if you don't have a real need for an office, but your employer prefers that you have one, look into some "virtual" office service such as Regus offices.  I hear them advertised a lot on the radio.  You might even find that your employer could find it less expensive than "keeping" an office of their own.  Is it essential that your business remain in the NY/NJ area?  If not, I'd try to convince them to let you look for a place where business rentals would be less and that you could maintain within an area with a lower cost of living.  (Oklahoma is good.....)

If you do sell the house and need to live elsewhere until the RV is purchased, I'd go with an extended stay place where you wouldn't be locked into a longer term lease.  After all, even if they have to build your RV, it should only take a few months for that to happen.  Our Mobile Suites was built within about 12 weeks back in 2010.

Good luck with all the planning and research.  Here's hoping that you can move offices to a state where some good RV parks are located.  Also, as Vance suggested, consider some of the mobile home parks in an area if you still have to live and work for a spell.  We are staying in one here in Oklahoma where our lot rent and utilities are less than a monthly rate at the RV park next door.  In addition, we were able to select a good lot with a nice "yard."  We were able to use some existing fence that the mobile home park had on this lot and with some temporary fencing from the hardward stores, we've got a really nice yard for our two Miniature Pinschers.

Now, if a long term stay in an rv park/mobile home park is not in the cards, then a yard would likely not be important.  In our case, perhaps rare, our monthly lot rent is less than $190 and includes water and sewer.

Terry