Why don't you make a trial run in your driveway to see what you need to do...
What works best for us with our 30AMP Trailer is having a 10-gauge (10-3) extension cord and we use the RV30A-15A long "DOGBONE" type adapter. we can run just about everything in our trailer with the high current items like the A/C or Microwave only 'ON' one at a time - otherwise it will trip the house/garage breaker...
Your DP is probably a 50-AMP service which will work just fine plugging into a 15/20AMP service using the proper "dogbone' type adapters...
You will most likely have to plug your 50A Shore power Cable into a RV30A-50A adapter first then use the RV30A-15A adapter. NOTE the 30A-50A adapter has both 50AMP zones connected together in the adapter so both zones will be fed with the 15A/20A service. You will have to flip some breakers in your dual zone power distribution panel to make sure the 15A house/garage will operate enough without tripping the house/garage breaker.
Doing all of this at home before you go on your trip will really work out for you finding out what you can and cannot do...
Roy Ken