They essentially want to know your whereabouts at all times. So, anytime you enter the country your address MUST be reported to immigration within 24 hours. It's the law. When you're just reporting back into the same address, it's easier/less time consuming.
Very easy border to deal with. Bear in mind that you can only do two exempt entries by land per calendar year. If you have already done this twice, you have to fly in or go to somewhere like Vientiane and get a real tourist visa.
CM is not as strict as BKK so chances are you'll be fine. If you have a long history of tourist visas/exempt entries to Thailand on a visa exempt entry, it would be advisable to have 10,000 baht (or equivalent foreign currency) in your pocket as you enter thailand as it can be requested you show you have the funds to support yourself. They can also request hotel booking and onward flight. But again, this usually only happens if you do frequent entries to Thailand.
Btw, if you plan on staying for more than 30 days, why not apply for a 60 day single entry tourist visa in Yangon while you're over there?
Go to Vientiane and apply for single entry tourist visa (60 days)...1000 baht. You can extend this visa at any immigration office in Thailand an additional 30 days for 1900 baht.