Q. Which one is better for a long drive and good mileage combination when compared with Activa 5g & Suzuki Access 125 & TVS Jupiter??????

Honestly, none of these are meant for long drives. For long drives on step-through scooters one needs to buy something like Burgman400 from Suzuki. The relatively smaller tyres than motorcycles, shorter suspension travel, wind resistance, smaller fuel tank etc. will make scooters ideal for city commuting. Now if your definition of long drives are

I would recommend activa 5g as it has ample mileage of around 50km/l, good torque and pickup and excellent performance in highway rides.

The Jupiter is a good scooter, with a very good suspension setup. However, TVS service is not on par with Honda, and over long term, the Jupiter is known to have rattles and small niggles.