I changed to LED bulbs in our 2005 Crusader. I used G4 2W COB led's for the spots.
For the larger oval lights, I used some 12W led strip like this - https://www.amazon.co.uk/gp/product/B00JQV6SFU?tag=ukcampsite00. I soldered 3 short lengths (that would fit in the light) together for each light and you also have to remove the ballast thing. It was a bit fiddly and the soldering took a bit of time but it worked in the end... I would get non-waterproof led strip as the waterproofing is a pain to get off for the soldering.
There was a video/webpage showing how to do this but I can't find it.
A day of all things motorhome and campervan. The show is held both in the main indoor arena and across the grounds. Catering, hot drinks and food options are available. Easy access to the site and free parking included. Win one of five pairs of day tickets