Hungarian Grand Prix - follow on week or two?

[Inspectorclueso]

Just booked Hungary F1 next year as it works with the school hols for my boys etc...

I'm keen to make a trip of this and follow the grand prix with around 10 days somewhere (or multi centre). I'm thinking about getting he sleeper train down to Split, then taking some time in around Split, or Croatia in general.

I'm really after a good resort / hotel where we can relax for a week or so. There'll be 2 adult, 3 kids (17,15,12)..

Has anyone done this, any decent places to go that are practical after the Grand Prix....?

Any recommendations for Croatia or neighbouring / fairly local countries ?