Congrats! Nice start. You should have a ton of fun! Definitely post up pics of that sweet, new rig when you receive it. Build threads are great to keep all truck mods and questions in one place.
Be careful with the sand. It can get into places you don't want it, but honestly it shouldn't be a huge deal on this truck. May just demand more maintenance.
You're fine to start stock. There's absolutely no need to even think about changing anything until you drive the truck a few times first! As you drive and gain more experience, you will determine what you like and don't like about the truck. This leads to a logical way of thinking about upgrades or changes.
One word - haters. And Traxxas has more haters than any brand in RC. Companies on top often get the most hate though.
I've never killed a Traxxas motor, ESC or transmitter. Their servos are definitely the weak spot, but good thing the aftermarket for servos is massive and fits any budget!
Exactly. This truck should provide years of trouble-free fun, within reason, except for the servo. But again, don't worry about that until it happens. And when it comes time to select a new servo, we can help you find one that fits the truck and your budget.