That hard part of the 30 to 50 conversion is pulling the 6/3 romex from the entry to the breaker panel. The rest is just tediously swapping the connections to the new panel. If pulling the romex is easy access then the upgrade is a slam dunk.
Could also use a load shed device.
http://www.bestconverter.com/Automatic-Load-Shed-_c_96.htmlYou could string a couple of these on a single circuit to give priority to Coffee then Microwave and lastly Water Heater or your choice to keep the air running.
Or put something on a separate power inlet to grab power from the separate 20a GFI on the pedestal.