I converted my 37ft RV to LED last year for less than $100. I ordered these from eBay. They came from China so it took several weeks. Search Ebay for
"48 SMD Warm White Light Panel T10 BA9S Festoon Dome 48 LED Interior Bulb Lamp".
1. It's a rectangle panel of 48 LEDs.
2. They cost about $2 each and have connectors for 3 plug types.
3. They are much brighter than the standard bulbs.
4. All 20 that I ordered worked great. (I've ordered more to do truck map lights and add more light to storage area.)
5. They come with an adhesive back.
6. My closet had the single fixture rather than the double. So I wired two panels together and added to the single bulb outlet. They draw much less power so it worked great.
This is easily the cheapest way to do the conversion.
~$2 each on eBay.
Robin