As for a new plastic .30/06, the Remington 710 is hard to beat for value. It's hard to beat Ruger customer service, though.
It is a fact, though that Mil Surp .30/06 is drying up, and what is out there is probably pretty old. I'd suggest something in .308. That ammo is available pretty much where ever hunting licenses are sold, and can be had on the net in the form of Mil Surp pretty affordably. And as for versatility, the .308 can be had in everything from a dinky little 60gr (I think?) Acclerator bullet up to 180 gr slammers. This round will pretty much do everything that a .30/06 will do.
The idea mentioned about Mil Surp rifles is also a good one. Mauser made a bunch of 98Ks in both .308 and .30/06, besides the more common 7mm, 8mm, 6.5x55, etc... There are also a lot of re-fitted 98Ks in .308 floating around. For the price, a Mil Surp Mauser, for your applications, would be pretty hard to beat. You can find scope mounts for them still, and there are plenty of stripper clips available for fast re-loads...though you can't use both a scope and stripper clips. There are also plenty of synthetic stocks to be had for these rifles. IMHO, the standard issue sights suck, but they work, and can be changed out too.
If you look hard enough, you can find a .308 Mauser 98k for well under $200...so I would have to recommend that to you.