Are u looking for an elite cap lvling or wider range lvling?

If only lvl cap, there are basically 2 options. Faster and easier is the mega maze but it costs quite a bit of plat. The other way is to farm at Lost Valley. There are some ppl who like to exp farm at Dragon's Nest but compared to Mega and Valley, it isn't that effective.

Mega is easy to do even alone and it gives the best time/exp ratio. Lost Valley costs less plat but is a bit slower than Mega and also finding a decent group for Lost Valley may be a slight challenge.