I've participated in several different playa weddings.
What really worked:
Sunrise ceremony -
1) It seems it's actually easier for burners to make it to something at sunrise,
2) the light is amazing,
3) less distraction, especially at art installations.
Art Car -
1) One couple's camp arranged for an MV that could hold the entire wedding party & guests;
They were ferried to the ceremony site (deep playa art installation), then to the Temple for photos and blessing, then to a camp that
hosted their wedding breakfast - awesome!
2) Another couple was delivered to the guests at their ceremony site by two different 2 person vehicles - cute!
Food - Provide some!
1) Sunrise calls for a coffee station at the gathering place,
2) Cupcakes are great and easy!
3) Bacon is always appropriate!
Decoration - bring fabric scarves in your wedding colors for the guests to ceremonially decorate your site;
then they can keep them as mementos
Bells are fun - if every guests gets/has a bell, they can 'ring in' your vows.
Congratulations, and good luck!