Highway 14 is part of the "beltline" between its intersection with Park Street (going straight south from the Kohl Center area) and University Ave (in Middleton), so that could be a range of areas.
Either way, you're on the preferred side of the isthmus-related chokepoints/bottlenecking for getting to the Kohl Center. If you're driving in the 5:00 hour, you might get a bit of rush hour traffic on Friday, but you'll be going in the lighter direction, so it's not particularly bad. (I say that with more confidence if you're coming from the far west side rather than the south since I have more experience with those particular patterns.) During the tail end of rush hour, you will encounter some slowdowns in the immediate campus area, particularly if you're moving east or west along University, Johnson, or Regent. If you're driving up Park St during that time, you'll get some noticeable traffic, but it's generally moderate.
You can find free parking on campus lots that a) are free to park in during after-hours and b) aren't for paid event parking. Somewhere on the UW website you can find a map of parking lots that shows which ones are permit-controlled at all times and which ones are only controlled M-F, 7-4:30 (something like that). Some lots become paid event parking, but if you drive a bit farther from the arena, there are a bunch of lots within a short walk that are free. Also, there's a fair amount of street parking (free) if you can find it. It's easier to find it south of Regent St; most curbs are full most of the time in those blocks north of Regent St and south of Spring St. (North of that, and street parking is out of the question until you get up around Langdon and State Streets, which I wouldn't recommend.) The neighborhoods south of Regent St are probably more accessible from the outside, and you'll get out of the worse traffic.
