Just a suggestion -- Perhaps these 1/4" wide sanding sticks would be
of interest for detail sanding. Reviews on the site are 4.5 out of 5.

The 1/4" sanding belts - the loops are shifted to bring fresh grit into
position - could be used on an improvised setup. They have 320 grit in
addition to the grits listed below for the kit.

I have not used these. Similar items are available elsewhere.

24 Piece Standard Kit Sanding Sticks
http://www.woodcraft.com/Product/2000274/1744/24-Piece-Standard-Kit-Sanding-Sticks.aspx

Sanding Stick Kits make sanding those hard-to-reach areas an easy task.
Newly designed pencil-type sticks are hexagon shaped for comfort,
feature thumb and finger supports, and hold 1/4" x 12-3/4" aluminum
oxide belts. The 6-1/4" x 1/4" sticks are made of impact resistant
plastic and have a spring tensioned back to keep the sanding belts
firmly in place or allow quick belt rotating or changing. The tapered
end can be used for intricate sanding while the flat side and rounded
end add to the versatility of the sanding sticks. 24 Piece Standard Kit
includes 4 color coded sticks and 5 belts each in 80, 120, 180, and 240
grits.

* Hexagon shaped for comfort
* Hold 1/4" x 12-3/4" aluminum oxide belts
* The 6-1/4" x 1/4" sticks are made of impact resistant plastic
* 24 Piece Standard Kit includes 4 color coded sticks and 5 belts
each in 80, 120, 180, and 240 grits
* Have a spring tensioned back to keep the sanding belts firmly in
place or allow quick belt rotating

No doubt there are other sources on the web for similar items.