Question 1) Is there any harm in doing this. Theoretically I should not draw more than 30 amps regardless.
Answer 1)The main breaker in your RV will limit you to 30 amps, Not only is there no harm (Well there is a very small (I mean microscopic small) chance of harm but frankly I do not see it happening outside of a lab. And this is the field I studied).
The adapter takes care of the differences between 30 and 50 amp.. The biggest difference is this,, usually if you try to draw 30 amps or more the park breaker trips, not the one in your RV, so you have to go out and re-set it in the rain (of course).. With a 50 amp outlet and dogbone it will be the INDOOR breaker that trips, you do not get wet. That is the only major differnce, Secondary difference, 50 amp outlets are USUALLY in better condition than 30's so you get cleaner power.
Question 2) The bigger question is I have a 30 amp surge protector. Can this be used in-line with the 50 amp adapter? I really don't want to purchase a 50 amp surge since I would never really use it and if the surge is higher than 30 amp, the surge should trip.
Answer 2) Will work just fine, there is no problem plugging a 30 amp protector into 50 outlet via an adapter, since the adapter does all the work BEFORE the protector..Will work fine, Done it myself back when I had only a 30 amp protector.
Home is where I park it!