Boston is a compact city but it is still a 2 to 2 1/2 mile walk from its entrtainment and bar area near Kenmore at its commercial southwest to the North Station area at its commercial northeast. In between are the uptown back Bay, Copley, Park Square, Haymarket/Fanueil Hall and North End areas. (The Omni Parker House is located between Park Square and Fanueil Hall - closer to the latter). Then there is Cambridge, too!!!! The subway does connect them all, but it stops operating a little before the bars close.
there are quite a few sites that you can search that will likely show you great hotels at the best prices available. check out the website BookMe and you will be able to compare prices on all the reputable travel sites in just a couple minutes. it s very convenient and will save you a bunch of time and money. Also, make sure you buy them online... otherwise they charge much higher fees for phone orders. good luck.