wv, I wouldn't mix a grass & clover unless you or someone would be there to mow it a couple times a season. The grass will choke out your clover, becasue it'll grow so much taller. I once planted a strut & rut mix, which was basically clover & annual rye grass. I wasn't able to get it mowed as soon as I should've, and the grass grew knee high & choked out alot of the clover. I had to replant the clover the following spring.
Your in a tough situation by only having a few wks to do this, and then leaving it. A annual might be your best bet, if able to do it both yrs your back in the area. Something like Imperial No-plow annual mix. Another thought would be do you have another operating farm down the road aways. Maybe speak to them & offer the area to them to plow, plant & maintain for you. I know farmers are often looking for new fields to grow their crops on.