I had a Stumpjumper that was a really good value. I saw some Marin's in your price range also that looked terrific. One had discs brakes that could be very nice to have in your neck of the woods as they'll handle nasty conditions better. I've had 2 Marins at various times in my life and was very pleased.

No, lockouts are not the standard and add a teeny bit of weight. However, before you spend the money for lockout and you have a choice between 2 equal bikes, go with the lighter weight bike. Since you'll be buying a hardtail, you've already got some efficiency in the rear. When you go on the rails to trails ride, invest in some narrower, less aggressive tires like semi-slicks or slicks. I assume your rails to trails are somewhat groomed? They're not like a true loose dirt trail? On a 50 mile day, you will appreciate the lower rolling resistance of a narrow tire and a lighter bike more than a lockout.