Where to Enter & Paddle Out?
There are really only three reasonable access points to the surf at Sunset: the dirt ramp just past the east end of the Gladstones parking lot, the wooden stairs about 100 feet west of the lifeguard tower, and the sandy beach just west of the Bel-Air jetty. All three access points are marked for your reference on the Map of Sunset. I wouldn't recommend scrambling over the boulders to get down to the beach, especially if you are carrying a longboard. But lots of anxious surfers do it, and a few bust their arms or crack their ribs every year.
Whatever you do, make sure to take note of the tide level when deciding how to access the surf. While it is pretty easy to get in the water if the tide is 2 feet or lower, above that level it can start to get a little hairy, especially at the ramp. Even the wooden stairs get difficult to use when the tide is above 3 or 4 feet. At super high-tide, your safest bet is to go all the way down to the Bel-Air jetty and walk up the soft sandy bank. Of course, high-tide is rarely surfable at Sunset, so you probably won't be tempted to go out then anyway. (See When Does it Get Good at Sunset?)
Once you are at the shore, paddling out is usually pretty easy, since Sunset has a notoriously soft wave. You will need to carry your board out at least 10 to 40 feet into the water before jumping on it. The bottom can be very uneven with lots of craggly rocks, and you don't want to bust a fin or slice your board before you've even caught a wave. I would recommend an optimal route, but the bottom is constantly shifting, so you just have to scope things out. In the winter, the NW swells usually fill in the bottom with new sand, but the summer swells often take the sand away, and every new storm changes everything.
In any case, if it is your first time out at Sunset, I would suggest you use the stairs. The ramp can be a bit precarious to negotiate and it also leads to the more advanced area of the break. You would be wise to paddle out in front of the steps or the lifeguard tower where the waves are typically softest. At that point, you can assess the situation, and if you are a reasonably experienced surfer, then consider paddling out towards the point. If you are not an experienced surfer, stay away from the point. This is where the fastest waves are, plus it harbors the most powerful impact zone and the better surfers. (See What are the Best Surf Spots?)
The only time it ever gets seriously challenging to paddle out is when a storm delivers consistent overhead surf. Every once in a long while, there can be ten-foot plus faces at Sunset that produce some powerful white water. If waves of this size are consistently pounding, getting past this white water can be tedious. I have witnessed surfers trying to paddle out to the point in such conditions. A half hour later, they were still trying to get past the white water, only they had drifted all the way to the Bel-Air Bay Club. Unless you are an experienced surfer and a strong swimmer, I'd advise you to pass under these conditions. Just so you know, surfers have died at Sunset. They have also been rescued by lifeguards, Coast Guard boats, and according to rumors, even by helicopter (but the latter I have not witnessed.) Use common sense, be humble in the presence of the ocean's power, don't pretend you are a better waterman than you are, and you will be fine.