In reply to Jane Pea:
Hi Jane,
Thailand has many other venues aside from North and South however they will be your easiest venues to travel to. Unless you are specifically seeking grades of F7c and above (Chiang Mai has a couple of F7c's and a single F8a+) then the south is a beach and climb experience and the north is solely focused on climbing.
Having developed Chiang Mai since 2000, it is a good destination for plenty of routes from F4 up to F7b+ (with the odd harder line), away from crowds and in a fantastic part of the country. The disadvantage is that you can't just stroll down to the beach and 'tie on'. That said the travel distance to Crazy Horse is only 50 minutes and CMRCA have that side of things dialled in for anyone needing only transport (lunch is included with unlimited water).
Both destinations are certainly worth a visit.
For Vietnam, I have not visited Cat Ba but have developed a brand new area 3 hours north of Hanoi. This area currently has the longest route in Vietnam and about 30 other routes from F4 to F7b. Long single pitches on very good quality limestone. This is the main place that Vietclimb, based in Hanoi, visit on weekends. Whilst probably more 'remote' there is a community regularly visiting and thus you are more likely to connect with other climbers.
Have fun,
Francis
Post edited at 20:39