Congratulations on your new machine! Best wishes for many smile filled miles.
If I am reading you correctly, you are going to have the service work done at a shop. If so, they can completely inspect the beast for you. The shop manual for my 15 Gunner shows a service at 500 miles and then again at 5k miles. Did the former owner let you know if the 500 mile service had been done?
I would change all the fluids less the fork oil. The shop manual for my 15 Gunner calls for fork oil replacement at 15K or 2 years, but I would ride her for a while. H-D has extended the service intervals for their front forks, I believe, due to better seals and fork fluid. Back in the day, 2 years was the conventional wisdom.
I like checking the plugs, checking the battery connections and the Seafoam TX. Seafoam works miracles and the chances are that your pump can handle one application. I am not familiar with the XC air intake, but, if it is such that a critter could get into it, you should probably take a look.
I should ask if the exhaust and intake are stock. If the intake has been modified to breathe better, and no changes have been made to the air/fuel mixture, she could run poorly - and hot.
Whatever needs to be done to get her in shape, it will all be worth while.