The whole idea of riding motorcycles in Thailand to travel is a very toxic topic.
Personally, i have ridden a lot of miles here without a problem but i would probably be classed as an experienced rider, i got my first bike at age 7 and have ridden all my life in a few different countries.
Back to topic, i personally have travelled from Sukhimvit Soi 42 to Lom's bar on the esplanade in Prachuap Khiri Khan in 2.5 hours, for the unfamiliar with the area, that is 100 kilometers past Hua Hin.
That was on a motorcycle, and for those who call BS. there owner of the shop i was at in BKK will back me up as he has been trying to match that time for a while now......555.
So, in a nutshell, Hua Hin Is not that far.