Take your time, enjoy the ride. Lower speeds make for less tiring riding, especially if new to distance riding.
Pack/dress for rain, hope for sun!
The 650 has a great tank range, especially when ridden modestly. So chances are you can do the ride to your location on a single tank. This means rest stops don’t have to be fuel stations.
In terms of the bike. As you already mentioned, check tyres, tread and pressure. Lube chain. A quick glance over using the POWDER list, (Petrol, Oil, Water, Drive (chain), Electrics, Rubber).
Check the oil level.
Have a good first ride out. You have a great bike for it!