Surfing Waves

I am 5'10, 205lbs. Not chubby, just muscular. 23yrs old. Have snowboarded and skateboarded all my life. Live in Colorado, but surf two trips (a week each) a year, so not a lot. Have always been on lonboards, a couple mini-mals, and have tried shorter boards but they just wont hold me. Friends have always pushed me to check out a fish, maybe 6'5 or larger, 2 3/4 thick as I progress to shorter boards.
Any recommendations? Again, I would call myself an intermediate surfer, but just having trouble finding the right board.
Thanks

One thing to learn in surfing is to surf for your own needs.
You will be struggling at this stage if you go a low volume route,.
You can go a decent longer shape with some width and thickness that will do everything you need especially if you are "intermediate", I wonder how you are rating that?
Go too short and you will get frustrated, the more capable the more you can cut down on length and volume it is also worth taking into consideration where you are surfing and being brutally honest about your own abilities and those who are advising you.

If your friends are following fashion and being cool forget it!
Go out surf lots as much as you can from Colorado and you will know when you are ready to step down!

Surfing only 2 weeks a year? Stick with the longboard and pass no heed of your mates... end of.
If you want to progress down to a shorter board.... move closer to the surf. If you only get 2 weeks a year, you don't want to spend them struggling and learning to surf a shorter board. You want to spend them surfing as many waves as possible.

It's just not possible to progress on to a shorter board with how infrequently you surf. Any progress you make will be completely lost by the time you get out again. Keep the longboard, catch heaps more waves than your mates, and go home miles happier after your surf trip.

Pretty much going to repeat the last two posts .
On your next trip suss out a hire shop. You many be able to hire a few boards and test out a few boards to find out whats right for you. Local shapers often have test boards also. Check them out and talk to a shaper. Otherwise it turns into a very expensive mission (even with ebay).
Aloha!