I don't support and I will never vote for Trump, however I think his VP pick is extreamly important as I think its very likely he/she will fill out his term in the unlucky event Trump is elected.
Serving as president will put a severe crimp on his lifestyle, for most life in the Whitehouse is imprisonment in a gilded cage, for Trump it is likely to feel like imprisonment in a flop house in a third world country. Trump is used to telling people where he wants to go and when, the SS will tell him when or if he can go.
Trump is a hands on guy in his day to day businesses, he will have to give that control up and put everything in a blind trust.
If the make up of the next congress opposes him at every turn and makes it their number one priority to prevent his reelection, and conservative talk radio turns against him due to his inability to make good on any of his promises, then I think he will take his ball and go back to his very nice home.
IMHO who he picks as his VP has tremendous significance.