>>>> "Can anyone help with general advice on buying land for living on ? such things as is it worth buying land from county lien sales?, It look reasonably straight forward compared to UK but what are the major pitfalls?" Looks can be deceiving.... Every state, and sometimes every county within a state, will have a different set of rules/requirements.

Being from Scotland and all, you might want to keep in mind that climates within the individual US states can vary immensely, depending on where you are. And, you need to be aware of just how brutal a summer can be in many parts of the US, even parts of the country outside of here in the South, and how brutal a winter can be in many parts of the US that you might never imagine such could be so can indeed be too.

My advice is to have your son choose what school would best suit his needs and plans, and then start y'alls quest.

You need to do that first as you will soon discover that zoning and codes and restrictions and this and that and some of the other too can vary from incredibly restrictive to practically non-existent by simply crossing a county line. And it's somewhat the same with land prices too.

The link below might offer you some help in deciding. And here too:
www.landandfarm.com

Oh yeah.... Your son will do just fine here. Seems as if I remember that if a guy from anywhere in the British Isles walked into anywhere and spoke, he instantly became the most desirable male around. Sort of like how popular a guy from way down south walking into a bar in New York or Minnesota or Wisconsin and saying "Hey, how y'all doin" suddenly becomes. With the ladies anyway...

Here is a link that might be useful: A place for starting out looking

The most popular states for homesteading to me are in the southeast and Texas. The midwest also isn't too bad though there is more winter involved and a lower growing season, though you can often get winter crops.

I would look into zone 7-8 as you can grow peaches, blueberries, cherries, apples etc. Around Nashville TN is a nice area, Columbia south carolina have a wide growing season "and your only 2 hours from the beaches and mountains".

Texas might be good with your engineering background, but Texas colleges tend to be more expensive. Cali is often too expensive to homestead. NC might be a very good state as well, it would allow for easy travel, is very temperate, and you can grow a lot of stuff there.