Travelodge is very close, yes. It's grouped in with a BP service station & little chef on the side of the A14 dual carriageway (usual kind of setup). You will need to drive from the hotel to the venue though, as you're marooned on the side of a busy dual carriageway, there is no pedestrian access to it. Will be more than a mile to wicksteed park though as you have to drive almost a mile in the wrong direction to turn round, drive back past where you came from and then turn off towards the venue!
It'll be fine though, as good a place to stay as any really, no probs
For anyone else's information the only other two real contenders are Premier Inn (just a couple of miles further away on the A14) or Holiday Inn which is yet another couple of miles around the ring road - it's slap bang on the opposite side of town from Wicksteed Park but Kettering isn't a big town!
Whichever hotels you use you're no more than 5-10 minutes away by car.
There are a few smaller B&B type hotels nearer in town to the venue, couldn't tell you what they're like as I have never needed to get a hotel room in my home town as yet!!
I'd avoid the Royal, The George and The Market Inn as they are all in the town centre and noise/parking will be a nightmare. Not sure if a couple of those are still open, they all seem to be changing hands and opening/closing all the time.
Kettering Park Hotel is fooooookin expensive, you'll have a lovely stay there but not exactly budget accommodation. Probably the closest hotel to Wicksteed park actually, thinking about it!