Jenn, kudos on your walk. I have to plump up my veins for bloodwork, too, even when I consistently drink 64 oz. per day. But I do have large veins on top of my hands and it doesn't bother me if they resort to taking blood from there. Wishing you really good results.
Age 67, 5 feet tall
Highest weight ever in the fall of 2010 246 lbs.
FitDay starting weight 1/17/2011 240 lbs.
Weight 12/18/2013 on my doctor's scale 231 lbs.
Weight 1/2/2014 on my new home scale 229.4
Weight 3/7/2014 225.4