Cowboy Al,
Not to rain on your parade but,140 acers is no way near a willderness experiance.I have a feeling there is a pen involved.
As for caliber,if penned game is on the menue then the .243 is perfect.Now if this a legitimate elk hunt with plenty of varitbles,you might wanna get your self a new gun,I mean why spend 7k on a hunt and not have the right tools.Since you are a novice at hunting elk I will say this.If you can shoot a 243,you can handle a 25-06,you can handle a 25-06,might as well try a 270,since the 270 is not that bad go an buy a 30-06.Put a 3-9 scope,box or 2 of 180 gr Noslers,nice sling and have fun.
BBJ