Yes, it would require maximum allowable crop density to get it done. It'd be the only way to grow enough food to get the job done, and yes, it'd be a lot of work. In fact, maintaining the crops would be a full time job for every able bodied member of the family. You would not get a suitable yield from wide bed cropping on only 5 acres.

I've done high density gardening with another on an acre. We each spent an average of 20 hours a week and the yield was considerable, but I don't know as I'd want to do that amount of gardening like that ever again if I didn't have to. It's like you couldn't ever do anything else except what you had already worked into the routine, and for 6 months of the year that was rough, and a lot of it was done with a hoe and a small Mantis rototiller. We sold most of the produce at the farmer's market on the weekend, and I figure for the time we put in we probably each made about a dollar less than minimum wage for our effort, if you discount all our expenses first.

We did learn an awful lot about basic gardening. Mostly, it is time consuming, tedious work that'll make your back ache.