Welcome to the group, ride safe.
You bike's model is somewhat rare on this site. Personally, I can't comment on anything specific to the 400. However, in general (and in no particular order):
1. Tires - check the date stamp. If older than 3 years, regardless of wear, pitch 'em. It's dangerous. If you end up replacing your tires, while the wheels are down, examine the wheel bearings and replace as necessary.
2. Manual - get the Cylmers or Honda service manual for your bike. Check here is you can't find one:
http://www.helminc.com/helm/homepage.asp?r=3. Alternator - check your manual, but I would imagine you should expect about 12.5 volts with the engine off, around 13.5 volts with the engine running at least 2500 rpm. The stators on these bikes don't put out at low rpm.
4. I'd change the oil and filter (if it has one) pronto. Cheap insurance. Be sure to use a motorcycle-specific oil.
5. Bleed the front brake to flush out the old fluid. If the clutch is hydraulic, bleed it also.
6. Chain/sprockets - check for wear, excessive stretch - clean, adjust, and/or replace as necessary.
7. Examine the air filter - if it's dirty, replace it. I'd be leary about pitching the stock air box and replacing with POD filters - that will likely require carb re-jetting.
8. Lubricate the clutch cable. Examine it and if frayed - order a new one.
www.bikebandit.com9. Make sure all of the lights work and the horn. Test the emergency kill switch.
10. Get the friggin riding GEAR!!! Don't play around. You don't want to take the pavement ride without it. It might save your life.
and most importantly.....
Enjoy your new toy. Have fun and post a couple of pics.