Hey man!
Sounds like quite the trip - I'm jealous. You'll be fine on your 150.
A couple of years ago I rode a 110cc about 1500 miles around the UK. I found anything over 200 miles a day to be a bit of a stretch, but you may have a different experience. Take lots of breaks, and you'll have periods where the journey is awesome, and parts where you're wondering why you've bothered.
Spare rollers, variator bushes and a spare belt are a must - make sure you're able to change all those bits over - have a practice before you go!
I took a hexi stove and cooked for myself wherever possible to keep costs down.