One thought...

If you're expecting about a year before you want to kill anything past 1,000, you might consider 2 rifles - and save this 300RUM for 8mos from now (but do buy it).

The barrel life isn't great on the RUM, and cost to shoot it is high, let alone recoil, so you might burn out the barrel before you get yourself capable of realizing the advantage of the RUM. As an example, I know that I couldn't capitalize on the advantage of Ridge Runner's 7Allen or 6.5 Gibbs or a 7Dakota over my 284win or 7mm Rem or 300win mags today. 10yrs ago, I could have, or maybe if I spent the next 6-8mos diligently practicing, but right now, I'd just be burning up barrels to practice my way back to that skill level with a 7mm Allen. I've been close to building a 338Lap a couple times in the last 2yrs, but if I'm honest with myself, any shooting I'd do past 1,000yrds would just mean it'd cost me more to miss just as much... I rebarreled my 6.5-284 to straight 284 for that reason - I wasn't practicing enough to be able to wring out the difference in potential between the higher bc, higher velocity 6.5 pills over the 7mm's.

You might come out ahead in skill level and finance if you picked up a 308win and spent 8mos to a year throwing pills at 600-800yrds from it, then bridged into the super-sport RUM when your skill gets up to the task of capitalizing on the ballistic advantages. Even shooting a 223rem fast twist with 75grn pills at 600-1000yrds can be a good option for learning the long range game.

That's a good deal on the RUM, I'm just thinking about how to maximize life on it, minimize your cost, and minimize your learning curve to be able to maximize the cartridge potential.