Ellie has made a number of excellent points, well catalogued. I would. add that being 69, and having bad knees, I really appreciate my raised beds - I have 6, all 2 and a half feet high. At the moment I don't have a perch seat on them but might do in the future. They are one meter wide and four are also one meter in length with the middle two being 2 metres. They are a metre apart with weed cover down, and mulch about to be laid between them, all enclosed by 4 inch deep planks to keep the mulch in place.
As Ellie says, grow what you enjoy eating and is not readily available in supermarket. I too only have a few potatoes, but I also have carrots, beetroot, dwarf beans, mangetout, and fruit bushes and strawberries. I don't have room for anything bigger than hens, except in my front paddock where I could have a couple of sheep but I'd worry they'd grow extra legs and walk in this area. So that's another thing to consider, choose your area well. When I was looking to move down here 5 years ago I made a mistake. I only looked on the big house estate agent sites not the specialised country ones.