Ride like uncle, just want a little more speed, and stable.

Seriously consider a scooter lah, forget about what people keep talking about expensive to maintain. Scooter is actually much simpler than a chain bike, less components to maintain.

Maxiscooter provides large underseat storage.
Honda ADV150, Yamana NMax / NVX are nice, Honda more on comfy ride with good seat position.

If you want walk through scooter, Honda Vario 150 is one to consider.