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?

I have been riding 2018 Honda PCX 150 since new, now clocking more than 40,000 km.

Maintenance can be cheaper than a similar sized kapchai - see here for compilation of 2 years maintenance / 24,000 km.

PCX can do highway but comfortable speed are around 90-100 km/h. It can do up to 113 km/h but the engine is in stressed out working condition thus no longer enjoyable. I sometime do day trip from JB to KL for meal tapau - yes can do.

For your purposes, I would suggest going for used Modenas Elegan 250 (without ABS) that are available for around RM8k. Highway cruising should be more enjoyable.