Allyson,
What you must do when you take out the policy is to notify them that you are insuring the caravan & X is the owner. Not usually a problem if the 2 are married, partners or related, if you fall outside of these criteria, they may ask why, but at the end of the day it really does'nt matter who's the owner & who's the insurer, just as long as there is no intent to defraud the insurance company.
Fact, my wife owns her car and is the registered owner, the car is insured in my name with her & daughter as named drivers (done this way, as I have a company car & this is the way for me to maintain my no claims discount, & yes I do know about direct line's named drivers on their policies earning NCD in their own right).
To answer your question number 2, When being towed, the caravan is covered by the towing vehicles insurance, NOT the caravan's insurance, so as long as you are the policy holder of the tow car (or a named driver on that policy) the you are covered.
BUT one word of caution, CHECK THE LEVEL OF COVER ON THE TOW CAR'S POLICY, if it's not fully comprehensive & you have an accident & it's your fault, the insurance won't pay for the repairs to your car OR caravan's damage.
Oh & by the way, don't forget to let your tow car's insurers that it will be used for towing, most policies include towing a trailer (& for insurance purposes a caravan is a trailer) but there's no harm in declaring it & that way it's on record & they can't wriggle out of any claim.
GeorgeB
PS how'd the collection of the new van go?