Hey. I've had type I for twenty years (my diabetes can drink this summer!) and been on the pump for somewhere more than five. Good for you for getting out and being smart about eventing. Davit's list is pretty comprehensive, so my #1 on events is "what he said".
2. If you're out fighting, make sure your infusion set/iPro/etc are placed where you don't normally get hit. For me, this is low on my abdomen on my left side--aka my shield side. * those things hurt when they get hit, swiped, or tagged with a weapon. For that matter, make sure your pump is secure in a pocket or strapped down somewhere. Having it swinging by the line from your skin is awkward and strangely embarrassing, and getting the line or the pump in the way of a swinging weapon is painful (and potentially expensive).
3. Don't stop at extra; bust out some of the supplies you used to use (like syringes) and bring those with too. If you've been out fighting all day, are sweating profusely, have just found your first patch of poison ivy, and for whatever reason your infusion set craps out on you, it might not be feasible to replace it right away. If you've got to wait for your temp to come down/skin to dry off/swelling to recede, an injection is going to be easier and less frustrating than wasting infusion sets that won't stick or that squeeze themselves out right away.
4. We metabolize things differently than everyone else. Be smart about your consumption habits. Don't toss your normal schedule out the window and don't go crazy with the alternative substances (if they're your thing) because even if the people you're partaking with know about your diabetes and your hypo/hyper symptoms, they might not be prepared for what you're like while drunk (etc) and it might not let them recognize the aforementioned symptoms as readily.
5. Make sure you get to an event in Illinois at some point, and let Davit or I know you're coming
THere's also a women-only forum on the boards here, and Ladybug (another type I) is over there a lot. I don't know how often she hits up this forum, but if your name is any indication you'd be eligible to post over there too. And like Davit said--PM me if you want to chat or have any other questions.
Welcome to Belegarth!