What is the best thing to do if you can only feed one time per day?

I own two horses, one is a 20 year old QH gelding hes 15.2 and about 1100 lbs. and I have a 11 year old TB mare that stands 16 hh and about 1200lbs. I am in a hard spot as I am only able to feed them 1 time a day. Right now they are eating 3lbs of ADM patriot performance and 1/2 lb of nutrena boost the high fat one. Right now they are being fed 2 times per day but it is too hard for me to get out the there 2 times. So I need to figure out how to feed them only 1 time per day as they are missing too many meals. Any ideas? I was wondering if I should add more "hard roughage" as in alfalfa pellets or cubes or some beet pulp? and up the adm to 5 lbs a feed and the boost to 1 lb per feed? Any suggestions?