Short answer: I think WVa would go 5-6 or 6-5 against our schedule. I think we would go 8-3 against theirs.
Now, the longer answer to explain why.
The top half of the Vols' card (#1 Bama, #3 UGa, #9 Auburn, #22 South Carolina, and #25 Florida) is significantly tougher than the top end of WVa's schedule (#7 Oklahoma, #15 TCU, #19 Texas, #31 Okla St, and #37 Iowa St). Average of Tennessee's top five opponents is a #12 ranking. Average of WVa's is #21.*
Now, the Vols' bottom half (Mizzou, Kentucky, Vandy, Charlotte, UTEP, and ETSU) is significantly weaker than WVa's bottom half (NC St, Kansas St, Texas Tech, Baylor, Kansas, and Youngstown State). But see, once the opponents get to a certain level of weakness, it doesn't really matter if this one is 20 points weaker than that one; you should beat all of them, anyway.
So it is really the top half the schedule that you have to compare.
I think the Vols can reasonably win 7 games this season, on our OWN schedule, which puts us smack dab in the center of the 5- to 9-win range of realistic possibilities. The five I think we'll have the hardest time with are those five at the tough end of our card: Bama, UGa, Auburn, USCe, and Florida. They're all ranked, pre-season.
But if we were playing WVa's schedule, only the top three teams would be ranked: OK, TCU, and Texas. The next toughest, Oklahoma State and Iowa State, are matched most closely to Mizzou on our ticket. With (fingers crossed) new and improved coaching, we should certainly be able to beat Mizzou this year. And we would be able to beat OK St and Iowa State, I'm pretty comfortable.
So yep, we would go roughly 8-3 against WVa's schedule.
On the flip side, ESPN's FPI is saying that WVa will struggle against six teams on their calendar: OK, Texas, OK St, Iowa St, NC St, and Texas Tech. That means (with the noteworthy exception of being slightly favored over #15 TCU) there should be no way WVa would fare well against any of the top six teams on our calendar. So...5-6 or at best 6-5 (if we give them an SEC equivalent upset to match what FPI thinks they might get over TCU).
Bottom line: the math, the objective reasoning based on CBS' pre-season rankings and ESPN's FPI, says we'd do better with WVa's schedule (8-3 or so) than they'd do with ours (5-6 or 6-5).
Seems reasonable to me.
* I used CBS' pre-season rankings for this comparison, because they go 1-128.
College Football Rankings. Also used ESPN FPI for WVa:
West Virginia 2018 FPI - Mountaineers - ESPN