Yes, I got my original character back to L25. I'm not the only one, though.
It was a daily grind of gathering up aether and putting it into an engine. WAY faster than trying to level up fighting. I'm a hoarder of resources, so I don't like to use up items for just aether, so that limited me to about 6 engine loads per day. 1-2 more when freezing the crocodile pools, but I stopped doing that when I had more tears than glass vials.
You can go a lot faster if you use items to generate aether, like helping the folks in urchin's grotto, putting up posters or plugging them into a repaired poster machine, using patches on air leaks (Flying L) or wind socks (snowmoors), or turning in honey/wool/milk in the Business District.