I'm glad you like the avatar...and yes, that's a good angle.
I did walk around the house naked when I was younger, and once my dad caught me walking into the shower with a boner. He didn't say anything at the time, but then commented later that I was developing nicely. I suppose he was well-hung, but it's been a long time since I've seen him naked, and I'm sure I thought it was bigger since I was a kid at the time, and he was a grown man.
I would say I'm averaged sized now, nothing to get excited over, but I think I look okay flaccid, so going to nude beaches isn't really an issue. I wouldn't ever worry about measuring up there though, as there are all different shapes and sizes and ages of people (and sexual organs) on any beach at any given time. I was self-conscious the first time, but I've also seen guys with boners walking around in front of kids. I think most people realize this is a natural thing that happens, and as long as you're not being blatantly sexual, it's not a problem.
I've also been to private-public swimming pools in Europe where women will go topless, or even nude, and this is considered perfectly normal in order to tan. There are also parks and rivers in Europe that are also nude friendly.
Even if you were confined to a wheelchair, I think you could still enjoy a nude beach. Some require that you are nude, while others are clothing optional...so it would be your choice.
And as to what surprises me when I peek: I was more making a joke, but I think every man is surprised when he sees a well-hung dick, particularly on someone that you would otherwise think was normal.