Just thought I'd quickly say thanks again for all the replies, hvae had some great advice from you all. The weather doesn't seem to worry me so much anymore, atleast we're going there aware that it may get a lil rainy so we'll be prepared.
We've decided to fly to Chiang Mai and back due to shortage of time between when we arrive in Bangkok and the beginning of our first package.
It's all booked now so am extremely excited!
Thanks for all your help!