TL;DR not worth the effort or risk.
I was in Venezuela at the start of 2016. we did Los roques for the first week and Margarita for the second. We knew it was going to be a bit dodgy from various forum posts about the areas. What we weren't prepared for was the cash situation.
YOU CANNOT GET MONEY ANYWHERE! there are NO ATM machines. You cannot pay by card because the official exchange rate is not used anywhere, only black market prices. You cannot get money from banks for the same reason, you cannot get dollars.
I was warned of the dangers for tourists by 2 Venezuelan ladies I was sat next to on the plane, they had left the country several years ago for europe because of the increasing danger in the country. Their hand luggage was stuffed full of grocery items, instant coffee, dried milk etc.. as the country is in such a poor state there are limited supplies of basic items.
Then we were warned again by another guy while we were waiting to go through passport control. He said don't take a taxi from the airport, they're not to be trusted. call ahead to our hotel and get them to send a taxi. He was an ex-tourist manager but has now moved outside Venezuela too. He said don't leave the hotel for anything, don't walk down the beach and don't go anywhere after 5pm. That was Simon Bolivar international, Maiquetia. We stayed at the nearest Marriot and flew out the next morning to los roques. no problems at the hotel, we changed some dollars for Bolivar with the taxi guys out front of the airport, but they were very nervous about the deal.
You have to take US dollars in cash and change it on the black market. We found a few places in los roques we could change money, in our posada and with the island ferry kiosk. That was kind of exciting as we had a backpack full of cash.
Los roques is paradise, no mistake, the water glows a fluorescent turquoise, a large ray swam past us in the shallows at one kiting spot, just amazing.
We then flew back to Somon Bolivar int and got a connection over to Margarita, we needed a bit of cash and did a dodgy deal with a porter round the back of the airport in a service lift that stank of piss, that was an experiance. He had wedges of cash shoved down his socks!. We stayed at El Yaque all week, in 2 beach front hotels, we changed half way through due to a cockup with our booking. The first hotel RAN OUT OF WATER EVERY DAY! There is no fresh water on the island and there used to be a pipeline, but it was shut off, so fresh water is now brought in by tanker. many hotels suffer the same problem. our second place seemed much nicer and had water every day.
We changed dollars regularly for wads of cash, either in the restaurants along the beach front or in the local booze shop. Again people were very nervous about the exchanges and were constantly on the lookout for police.
One night on the beach my friend got mugged by the cops. They came along and threatened to arrest him, he didnt have his phone or wallet but did have his E-cig so they confiscated that and walked off. After speaking with a british couple out there they said the cops regularly take the cash out of peoples wallets and are not to be trusted. she worked out there for 8 years apparently but not any more.
we then ran out of dollars 3 days before we were leaving. luckily we found a really nice british guy who was able to chip us some dollars and we paypal'd him back. We took just under $1000 US, our budget was complicated by the fact our hotel had no record of us booking and we had to pay cash, no card, no paypal.
El Yaque is absolute garbage for kitesurfing. its was cross shore in the afternoon and was super gusty every day. It seems like a great place for windsurfing though.
We got a ferry boat over to Coche a few times and that was a great flat water off-shore wind spot with clean wind. But there's not much there, just the kite school. They sell beer so there's that. no food over there though, not near that end of the beach anyway. Also the ferrys were extremely unreliable, we sat on the jetty one day for 2 hours and eventually went back to the hotel.
I'm not usually too concerned with health and safety stuff but half way across to coche on one trip the driver, while smoking a cigarette, pulled the fuel line out of one barrel dripping petrol all over it and shoved it onto another. no screw cap or seal, just a fuel line into a plastic fuel drum.
overall, los roques was fairly safe and El Yaque didn't seem too bad, but getting there through Meiqetia, the cops, finding money and the stories we heard it was just too un-nerving.