Since I was a kid I read about how Roman legionnaires, after finishing their tour of duty, would get some money and a piece of land to settle down on, as a reward. Lately it occurred to me that I never really thought about if that was actually a good deal; just checked if off as "oh, that's nice, guess they'll become farmers then." back then, naively picturing vast rows of neat rectangular plots covering the land.

So my question(s) is/are: Was the piece of land a legionnaire got actually enough to sustain him? Sustain a whole family? (by sustain I mean feed the people and provide enough excess products/materials to be traded for other necessities).

Expanding upon that two other questions:

1.) What did Legionnaires actually do with their land? Really just go their, build a house, start becoming a farmer? It must be more complicated, especially for people that have been professional solders half their life.

2.) How did those lots of land for legionnaires fit into the larger economic picture? Were they mostly isolated, sustaining their owners. Or did they play a larger role, maybe as provider for the military? Did they organize themselves, etc.?

Edit: I am aware of the broad socio-political reasons why Rome would want to settle their veterans in newly conquered lands; by all means feel free to explicate those aspects. The main focus of my question however are the micro- and macro-economic aspects of this topic.