Smokingrezel has described a common DIY cure - the best one in my opinion. Unfortunately, the plasma cutter and wire welder part kills that idea for most folks.
Samurai body parts are hard to find in the US, so you have to improvise.
A lot of folks take the bracket that holds the plastic rocker panels off with a grinder, remove the rust area, weld in new sheetmetal, seal the work then cover it with aftermarket or home-made rockrails. Another choice is to thoroughly clean out the rust,fill with insulating foam, sand smooth, then patch the surface with epoxy and maybe a piece of fiberglas. Top your work with rockrails to cut down on trail damage or to add some 'bling".
The only cure for the rear bumper is to get a new one. The chromed version may be hard to find. An even better solution would be to replace it completely with a tougher aftermarket one.
Here are a few links to OEM or replacement body parts:
SJ410 & SJ413 : Extremebends.com | Landcruiser Toyota Parts and EBI 4x4 Accessories
Showcars- All Your Suzuki Needs - Fiberglass & Steel
The above were found by selecting BODY
as a search category at Ack's FAQ (see link in signature, below) and leaving the search word field blank. There is also a couple of other links in that search that might be helpful to you.
I hope that his helps!
searchable links to the Samurai/TracKick
info that you are looking for!
'88 Samurai Offroader - HypnoToad
'88.5 Samurai Tintop Restoration Project - Bad CR
'14 Ford Transit Connect DD