Rob, I have had motorhomes for years. Most current is a 35' bus. It will pull 10,000lbs and weighs 34000lbs. I have never had to go through the weigh stations on the road, I happen to have a license with endorsements, weight, air brakes. Not necessary in most states. Unless you have an accident...be very carefull here. I think you need to evaluate several things.
How much room do you need to "live aboard" while on the road.
How much weight will you be towing. (remember if you purchase a motorhome that won't pull the trailer one or the other is useless)
What type of budget are you allowing to "get into the business"
Ready to go consession trailers can cost more than the motorhome.
Are you going to go from place to place or leave one parked in the same spot.
Make sure the genset on the motorhome is large enough to handle ALL the concievable loads while doing business. Or an aux genset is necessary.
Price great (read GREAT) ROAD ASSISTANCE (towing) insurance. A thousand dollar tow bill is hard to swallow when great insurance is only $100/yr
Have a real heart to heart with the better half and well then just jump in..nothing like being in business for yourself!
Best of luck..