As a kid most if not all of my riding was on roads so its what I know. In the Pattaya area are there a decent amount of offroad options to justify a mountain bike? If not I'll probably get something for the roads with an upright riding stance.

Depends on what age you are, I think at 73 whilst I am fit enough to do 50/60 K three times   a week on my hybrid , unfortunately  my sense of balance has gone  and jungle tracks with all that slippy  sand has me falling off just too many times for comfort.

 

Some of my friends who ride the jungle tracks on big tyres just dont like the Pattaya roads and feel much more comfortable  or should I say safe but generally  I find that  most of Thai drivers are very aware of cyclists and M/C ists and leave plenty of space around me at least.

 

I tend to avoid Pattaya central roads but around Jomtien, Ban amphur, Bansare, lake Mabrachan Huai  Yai even on highway 3 down towards Sattahip the roads are most comfortable and relatively safe and if you venture to the area around Plutualang golf course very beautiful and quiet.