@shann As a festival veteran, using both pumps and MDI, it's much easier than you think.
Key points are:
Invest in Frio wallets to keep insulin cool
Always carry your gear with you - don't leave it in the tent for someone to nick
Take what you need, not excess.
If you're going in a car, leave a small cool box in there with spare insulin and supplies.
I've never really needed to take loads of snacks - just made sure I've got glucose tabs - there are usually tons of food outlets on site so you can treat quickly with tabs and then grab food from a variety of venues, but it doesn't hurt to have them.
Brush up on your carb estimation - it's going to come in handy when you're eyeing up pie and chips or burger and chips after a few drinks.
Practice your "testing whilst moshing" technique - don't want those test strips going everywhere....
Boardmasters is relatively small so there shouldn't be a huge amount of walking about the place.
As
@Ann1982 has said though, just enjoy yourself. That's the most important thing. People aren't going to care about what you're doing to yourself. They are too busy enjoying themselves...