Kerplunk, Ride your bike is really easy.
Dont have an expensive bike and make a side loading rack for your boards and your kites.
You can make one out of PVC pipe and hose clamps.
You can also just buy a trolley from super cheap auto and rack your stuff on that.
I have moved on from those and I have a Yuba Mundo bike It can carry 200kg on the back wheel so I can take my kides SUP and Kite gear all at the same time.
The kids are getting into surfing now so we are looking at getting a Quiver Caddy, (I just missed out on one on Ebay).
They fold up for transport
Up to you though go the cheap option so your bike does not get stolen. Every time I have been down the beach no one even thinks about our gear lots of locals know me and my kids so they warn people off.