We mooch-dock at a friend's house about every other year. They are kind enough to let us tap the 15A circuit by their front door. But it is way too far for our RV cable to reach, so I'm adding 12 gauge extension cords to bridge the gap.
I still put my Southwire surge guard in line between the RV cord and the 15A extension cords we use. We've had the voltage drop enough to trip the surge guard (not even trying to run the AC).
A 25' RV cord sounds like a good length to help you reach but not risk going too far.
Best regards,
Chris