[rack your brains]

This can be accomplished fairly easily. Assuming you have no current factory rack installed correct? If so then...

The Thule 400XT Aero Complete Roof Rack Base System will fit the 1992 Suzuki SideKick rooftop perfectly. No matter what gear you plan to carry on your roof, you will need a multi-purpose roof rack base system. The Thule 400XT Aero system includes four 400XT Aero feet, four FitKit 152 Clips (specific to your 1992 Suzuki SideKick) and two square load bars. Remember that you will need to choose the 65" length square load bars for your roof top so that you'll have enough room to attach the camping gear and surfboard carriers at the same time.

Then I recommend going with the Thule 554XT surfboard carrier, which is ideal for transporting your surfboards. Attaches directly to the Thule 400XT base rack load bars and can hold up to two surfboards. Add a second Thule 554XT setup for carrying an additional 2 surfboards.

Finally, for your camping equipment you should go with something like the Thule 602 Ascent 1100 cargo box (connects directly to the Thule 400XT Aero base rack bars). This model has ideal dimensions for your needs - 88.5"(L) x 28.5"(W) x 12.4"(H), narrow enough to work well with the Thule 554xt surfboard racks on the base rack load bars, while also offering plenty of room for camping equipment and general cargo gear inside the box.