[racer_d]

Anything is possible.. How much you want to spend (parts, preparation etc) is the key. A quality "new" dolly I think runs about $1000, maybe 800. A used steel trailer can be had for about $1200. Not sure how much insurance would be (trailers are historically cheap to insure)
My dad used to flat-tow his speedster and 914 back in the 1970s. I imagine on the boxster, to flat tow, you would need to make some ugly holes in the front bumper cap to mount the tow brackets.

Ideally, i believe, you would want to "dolly" tow Ass up to limit the wear on half-shafts/cv joints/transmission. However, this would mean you would need to remove the sterring lock on the column so the wheels could turn. Same would be needed for a safe flat tow as well. Plus, you would want/need some additional lights and signage to alert other travelers that the car is "in tow".

Not sure what year boxster you have, but lets guess that the average value of a used Boxster is maybe $25K, it sure seems stupid to "cheap out" on how you will haul it around, especially as it gets pounded by road grime, rocks, garbage etc that the motorhome spits up.