Too many variables to be able to answer your question, in terms of what it's worth. An M98 can span from a collectors grade K98 with intact Waffanamps (don't know how to spell it, but its the Swastika stamps) to a hacked up deer rifle. Do you have photos ? If so, it might be worth posting the photos on one of the C&R sites (Cruffler.com ?) and asking over there.
Me, I like M98s, but unless they are pristine collectors items, I regard any old M98 as a project for re-barreling and re-stocking. I paid $69 each for these mil surp skanky old VZ-24 8mm M98s and rebuilt them into 308 target guns. One right hand and one left hand. I guess that each gun set me back about $350, not including the scope. Target at the bottom is 10 rounds at 100 yards from the right hand gun (top).
Mausers have always been an awesome action, many, many of your sporterized rifle actions have been based on a mauser action for the better part of the last century. You can see them on Rugers, and any other custom rifle with an extractor arm on the main body of the bolt. Also, many sporterized versions still have the notch cut away from the receiver for where the stripper clips would have been fed in. In my years of hunting, I've carried a Ruger M77 with a Mauser style action and have had great success. I don't have but one mauser based action any more, but still a classic and very reliable.
As for your question on caliber, I know many hunters who carry a 7mm Mag for deer when they feel they may have to make long shots, or want the extra power, just make sure you don't shoot shoulder shots if you intend to eat any of that part of the deer, you'll have hamburger if you do. I've carried an older Remington 700BDL in 8MM Rem Mag and have taken many deer with neck/head shots even out to 200 yards, and with those didn't mess up any meat, but those were not body shots. I have made body shots with the 8MM out in Sonora area at distances at around 350 yards with little extranious damage, but that is with distance helping. At 100 yards or so, you wouldn't want to make that same shot, I've seen it, and hamburger is the only word to describe it.
If you like the rifle, try it out, if you shoot it well, then shot placement on game is going to be your key. Happy shooting!