Well, I'm not a complete novice with herps in general, I used to breed Beardies and leos before those markets fell on their heads and then I bred Chameleons and uros, tried frilled, but had to give those up. I've only had savs & tegus as far as montior-sique things go.
Now, I just keep a tortoise and a handful of beardies.
As far as the housing goes, I have a reptile room (a spare bedroom) right now, but nothing built that will house an adult monitor. (I just have a shelf/rack system in there now). And since I don't know of any monitors that brumate, I will need a large, indoor enclosure for them for the winter months.
For the last two summers, I have sucessfully housed my beardies outdoors and they did wonderfully. We have 10 acres with a lease on another 120 acres. So an outdoor enclosure would be possible during the warmer months but the winter, they would have to be housed indoors (we have below zero temps & 5 feet of snow at our elevation).
Sooo.....the other issue I would run into would be to monitor-proof the enclosures. Right now, my beardie enclosure is about 20 x 20 feet and we used fine mesh for the sides, which we buried down about a foot and flared under itself to help prevent digging. The mesh is small enough so that most insects and no birds can get in. The mesh is also small enough so the lizards cannot get their nails in to climb the sides. We built it up so it's about 6 feet tall and fully enclosed the top (think chicken coop) to keep cats/larger birds out.
However, I understand that monitors are larger, better diggers and much more powerful than my beardies...this is why I'm asking and trying to figure out which species may work best for me and that won't require super-high humidity, which is very hard to get in our environment. Plus, I'm an animal lover so I want to educate myself to give my potential monitors the best life I can. 
Thanks!
~Heather