which marathon

i am currently training six days a week to try to qualify for the 2009 boston marathon. the question is, which qualifier should i run?

i am going to do one of two races on october 19th... the columbus marathon OR the denver marathon.

both are flat courses. only difference - denver is a mile high. i am already going to be in boulder this fall... so no expensive flight needed to do that race, which automatically makes it the more logical choice. i guess this all pends whether i want to buy a ticket to run with full lung capacity or stay sucking thin air in the mountains.