I think it depends on what you grow to be honest.
If you grow fruit bushes and trees,potatoes,perpetual spinach, carrots, beetroot,leeks,cabbage/kale/sprouts and onions then you'll just need to keep on top of weeding.
We have raised beds and mow the grass in between once every 2 weeks.
Keep growing salad stuff at home where you can water and pick easily.
Maybe take a sandpit to the lottie and some toys and you should be ok for at least 1/2 hr- esp if you take a little picnic.

We spend on average 5 hrs a week between the 2 of us and we have a full plot with raised beds.
We now travel to France a lot and have had to re-think what we grow as our children have left home and I can't honestly keep asking allotment neighbours to water our plants on a regular basis.
Planting through membranes and mulching should cut down water loss and weeds.
I'd say go for it, but see if you can find one in reasonable condition so you don't spend ages having to prepare it.
Is your OH going to help out too?? If so....no problem!