What should first-time visa runners know about getting a Non-immigrant O volunteer visa and traveling from Mae Sot to Vientiane?

Good evening all, as a first time visa runner, like Justine, (off to Vientiane tomorrow night or Tuesday) I'm hoping for some wise words from those experienced. I'm wanting a Non-immigrant O volunteer visa.

First challenge, I'm leaving from Mae Sot, and the first plane out is 11.20, which means I miss connecting flights from DMK, and most from BKK. First thought I should bus down on Monday night to bkk, but then a friend said you can bus to Kon Kaen, and then transfer to go to Vientiane. Any thoughts??

Secondly, I saw a comment about paying for a Laos visa in USD to avoid being ripped off. How much is it?

Thirdly, I think I have all the paperwork. Letter from foundation, wad of paper, which I am assuming is foundations' paperwork, passport photos, copies of passport, and a semi-completed form, anything else??

ps if you can recommend a mid price hotel with brekkie, I'd appreciate it.

Thanks in advance. Cheers :)