Shouldn't be a problem. I ride my Vino 125 at WOT all the time, have taken 2 900+ mile trips on it at full throttle. It has over 17,000 miles on it, and runs like new. The ONLY way to ride a small scooter is at WOT, otherwise you will not ever get anywhere, or you will be in danger from going too slow. A 125-150cc scooter is just the right size for long distance travel IF you keep the throttle wide open all the time. There's nothing in reserve, but you shouldn't need anything. Just wear a bright orange vest and stay in the right lane.
I won't spend more on a bike than I think it's worth, but if it's a good deal, I don't seem to have a problem buying bikes I don't need.
2002 Vulcan 750, 2013 Royal Enfield B5
2001 XT225, 2009 Genuine Stella
1980 Puch moped