bodywork tips needed PLEASE

[fleetwood90]

whats up everyone ive been doing bodywork for about 2yrs but not much resto. the body on 1990 fleetwood is decent but but it is a little wavy, my question is whats the best way to go about staightening it? just block the whole thing with 80 and use filler when needed or get it down to bare metel and skim coat the whole thing? It WILL be show quality any help or tips would be greatly appreciated.

THANKS