Planning to buy a 2nd hand bike as a alternative to driving

1. mainly to save some cost when balik kampung (Johor) from KL & reduce the travel time due to jam on PLUS highway. 
2. travel during peak hours after work.

Balik kampung trip is ~450km/ round trip with 50/50 trunk road & highway.
*Driving will still be my main transport going to work unless im going other place after work.

Plan to look for a PCX at 1st with a budget of not more than RM6k.
But the mostly PCX within that budget range will be ard 2015/2016, anything that I should be aware for when buying these bike (major servicing etc) especially those wtih high mileage >60/70k KM?

I have not own any scooter before. Has no idea with scooter maintenance. If major service is require, what is the range of the major service cost typically, so i can put it into my budget.

Open to any other bike suggestion too. My priority will be
1. Safety
2. Comfort

Speed is not a main priority, as long as it can maintain at 100km & with some power left to overtake is fine for me.

Am looking for PCX due to its CBS. My guess is that it will be useful when emergency.
Any PCX rider can provide feedback on this?