if by downtown you mean the Tremont/Washington Street areas.  That's probably the toughest area to drive through.

Copley Sq is probably the most convenient to the Mass Pike, the main east/west route.

The airport hotels are also very convenient to get to, but it's kind of barren out there.

it says, coming soon.
just wanted to look at your gallery.
thanks.

Hi Edrienne,
It's great that you're coming to Boston.  Are you accepting datecheck and TER for references?
Ciao

Be aware.  You may have trouble securing a room in late May for a reasonable rate in either Boston or Cambridge.  This area has one of the largest concentrations of colleges and universities in the world and the latter half of May overlaps graduation for many of them.  Room rates often rise during this period.

d_d

Like the financial district, there is plenty of daytime activity in Copley due to the business environment, but at night there is more to do and more activity in Copley.  Additionally, Copley is easily accessed by either the Mass Pike or the Greenline, and there are several upscale hotels in that area as well.

If you can drum up business in Des Moines, then Boston will be a walk in the park, so it probably comes down to where you might want to hang out for a few days.  And speaking of parks, the Boston Commons and the Public Gardens are a short walk from Copley as is the best park ever built...Fenway.  And if you one of several hotels attached to the Copley Square Mall, you'll have no problem finding a place to shop.

Just my $0.02