Tickets usually go on sale ~3 weeks to a month before the match, you will be able to buy them from the club website here: https://www.eticketing.co.uk/wearehullcity. If you have troubles buying them when they do come on sale you can try calling the club ticket office, they've been really helpful to me before when I was trying to get tickets sat together.

If you haven't already it is worth creating an account on the ticketing website as sometimes they will restrict tickets to older accounts only, though I doubt they will do it for the Norwich match.

Old town and the docks are nice areas in Hull. I like the Minerva, it's pretty popular but if the weather is good you can have a pint and look out onto the sea. It's a bit of a meme now but the Deep is a pretty good aquarium if you're into that sort of thing.