

The first date on the back is Halloween, so that’s clearly where the inspiration for the design comes from.
I don’t think you’ll find anything directly on the internet. The most promising approach would probably be to find a wedding registry in Buffalo NY and then look for October 31st 2009.
Boston and maybe even Essex could have been for visiting relatives/friends (or they initially met each other in Essex and wanted to re-visit that place too?); Qatar might just have been a layover for flying to the Maldives where the honeymoon finally took place. (Maybe November 28th was the last day and they decided to print that in order to frame the whole journey with start and end dates.)
I found the same skeleton on this T-Shirt: KKUP Radio 91.5 FM The Grateful Dead Marathon 2013, I can’t find the original artist, it could be that this was a stock image that was readily available for T-shirt printing.
Wow interesting! But did you get the shirt in the US, or was that somewhere else too?
I find it really fascinating that this shirt clearly meant a lot to someone, so they kept it all these years, but then still decided to get rid of it, yet without just thrashing it, AND then even in a different country/continent!
(I hope they didn’t just forget it in a hotel, which then decided to make a few bucks…)