Hi, from another 30yr old no wife no kids traveller.
$2000 a month or $70 a day is a decent budget for anywhere in the world apart from West/North Europe maybe.
You can probably go down to New Zealand/Australia, with a stop in SE Asia like others suggested, but I would add Burma to your list, its simply spectacular.
Have you looked at adventure companies such as Intrepid/GAP?
Its a hassle-free way of travelling, but with lots of independence.
Last year I spent 2 months on a truck trans-Africa, for about $4000 with Intrepid.
I understand about the private room, having done my fair share of dorms over the last 9 years of travel, I also need a private room nowadays. Its good that most hostels have private rooms these days.