Thailand forum

hi, i saw that a similar question was posted here earlier regarding visas for thailand however mine is a bit different. Firstly i am canadian and realize that i fall under the tourist exempt category, for stays up to 30 days. i am flying into Bangkok on the 15th of January and depart Bangkok on the 15th of March (total number of days is 60). i only plan on being in Thailand for 3 weeks initially and then depart for Cambodia/Vietnam and Laos. i would then return to Bangkok around the 11th of March. I am wondering if i will have a problem on arrival into thailand January 15th considering that my ticket has a departure date of March 15th and no visible proof that I will be travelling thru other countries as well over those 60 days. Will they allow me the 30 days even though my ticket shows i will actually leave the country much later? Or is it easier to just get the tourist visa for 60 days? Thanks in advance!