Well, with the right spell cast on you its very easy to go anywhere. However, soul linkers like mages are better in a party than solo'ing.
The good thing about soul linker is their ability to switch element, if you can get to know what is the weakness of each monsters, you will be strong no matter where you go. As for bosses, if someone tank for you and a priest heal, you can constantly do massive damage for 7k+.
I will probably play around a bit with my SL eventually, but right now im trying to get an other character to 99.
"The major difference between a thing that might go wrong and a thing that cannot possibly go wrong is that when a thing that cannot possibly go wrong goes wrong it usually turns out to be impossible to get at or repair."