I am starting to change over my old light bulbs for LEDs. I went to LED4RV and the guy there was very helpful. We have installed the warm light for most of our lights and they are a perfect match to what we had. In the bathroom we went with a "bright" light and it is much nicer when you are shaving or putting on makeup (the wife says).
In a newer trailer you might not have a fixture with replaceable bulbs. I was looking on replacing the entire fixture and the ones I saw all came as in integrated unit containing small LEDs permanently installed.
On most lights you can access the bulb by pinching the cover inward.
Good luck on finding the right intensity bulb. I can not stand that bright gymnasium look.