Hello Palustris, and welcome to our forum!
I can imagine you dont have a lot of spare time with a garden of those proportions.
I have 2/3 acre. The back of the house was a lovely flat expanse of grass when I inherited it from my dad - an open "full-sun" plot.
In the first year I cut out lovely beds and grew plants from seed - and lots of veg and "spuds" with great effect and results.
A friend suggested I should plant lots of shrubs and trees. I regretted taking that advice.
Now, I (like you) have taken a keen interest in Alpines, and would dearly like my plot cleared of those shrubs and trees. Every year, a fwe more are cleared.
The old saying Plant in haste, regret at leisure isn't quite applicable!
What are your favourite plants at present, and what are you planning to grow?