I choose a “trusted source” with good quality products even though the cost might be higher than elsewhere. My source was superbrightleds.com, and in the below list I refer to this source as “SBL” and list their part number. Even if you don’t buy from them, they list the specs which might help you. In fact, the Scamp
store is probably a fine source for the dome (921 type) and reading light
bulbs. All this information is for a 2015 Scamp
16 Std layout 4, YMMV.
The dome lights
are all 921 type bulbs with a wedge base. The stove-side dual bulb dome light fixture appears to use lower wattage bulbs than the single sink side dome. They were marked 12 watts and the sink-side bulb had no marking but did draw more current when I check it with a multi-meter. For the dual bulb dome light, bathroom, and sofa area I used SBL part WLED-WWHP9-DAC: Warm White. For the sink-side dome, I used the same bulb, only brighter, SBL part WLED-WWHP12-DAC: Warm White.
use an 1141 bulb, 1156 is a replacement and the SBL part I choose was 67-W15: Natural White. It has LEDs facing forward instead of all around like a standard bulb. I preferred the warm light of the original bulb so I kept one in place and use it when on shore power. In fact all the "warm white" LED bulbs are still less "warm" than the bulbs they replaced.
The “porch” light outside the front door, also uses an 1156 and I decided to go with a brighter amber colored bulb since amber light is reported to be less attractive to bugs. SBL part 1156-A27-T: Amber . This was the brightest bulb I bought, and with LEDs you pay for brightness... in this case about $20.
Tail/Brake/Turn is 2057 B14 dual filament, replaced with 1157 bulb (SBL part 1157-R3W-G: Red). Other running lights
(marker and second set of tail lights) will be ungraded only after the original bulbs fail.
I choose to leave the front outside light with the original incandescent bulb since it will be turned on only for very short periods of time. I also used a amber LED bulb with little light (30 lumens) in the dome light on the side of the stove-side cabinet for “mood lighting
.” It just enough to watch TV by.
Total cost was $100 and while there are cheaper options, I am happy with the quality of these bulbs which is better than some I had bought previously for my pop-up camper.
So the possible downsides are the initial cost, the fact that you might not like the light "color" and not getting the right or best bulb for the application.