There are a lot of people that put their bike in for a service or tune-up before their trip.
In reality you can do most of the basics yourself. It's also good to learn a bit about your bike just in case you face any kind of emergency on the way.
Maintenance Manuals (cough Haynes) are readily available online. You don't have to replace the fork seals, but there are great sections on regular maintenance which are well worth a read.
Also, there are many good bike specific forums and groups where you can ask for advice and there are some amazing web-mechanics out there.
We will be expanding this section soon, but here are the basics to sort out a few weeks before your trip
1. Check Oil levels
2. Check Tyre pressures and adjust if you are carrying pillion or a fair amount of luggage.
Check Tyre tread, you will want to stay legal.
3. Check your Chain and adjust if necessary.
Lube chain if required.
4. Check your lights, indicators and horn
5. Check battery, stick it on an Optimate or similar to top up or check.