The following requires a bit of flexibility but it's a lot easier then it sounds -- like trying to tell someone over the phone how to tie a shoelace!
Some folks seem to use a step-stool or Porta-Potty for getting into the upper bunk; I prefer to avoid clutter and simply utilize fixtures that are already there. The primary kitchen stove-and-sink cabinet seems pretty sturdy, and mine has no warning labels -- maybe the folks at Westfalia never figured some clown would STEP on it, but that's what I do.
With the top popped and the bunk deployed, simply place one foot up on the edge of the kitchen countertop, and with your hands grasp the the metal tubes of the vertical pop-top strut. NOTE: when grabbing these struts, be sure to apply pressure only in a downward or forward direction; if you accidently pull it backward you risk unlocking the struts' knee joints and bringing the roof down on your head.
Step up onto the kitchen countertop while steadying your upper body with the pop-top struts, and swing yourself over to sit on the forward edge of the bunk. The base of the bunk is comprised of about 3/4-inch plywood bolstered by a fairly sturdy metal frame. Nonetheless, such a structure is always stronger on the ends than it is in the middle of a span, so avoid parking your butt with too much enthusiasm right in the middle of the forward edge. Instead, sit off to one side while you scoot yourself fully into the bunk.
Once there, your body weight is more evenly distributed and there should be no concerns about breaking the bunk, although there is a thread on the topic of weight limits found elsewhere on the site: Westy Interiors > Bunks, Cots, & Hammocks. There is even some anecdotal evidence which takes into consideration a bedtime partner and "extra-curricular activities".
Since my wife doesn't like to climb down to use the potty we sleep down and stack all our stuff on the upper berth, On my last cross country trip I even took out the Fold over and mattress to allow for more storage. I made a plank that fit into the groove in the shelf to keep stuff from moving forward. When I did use the upper for sleeping I made a step to fit into the bracket for the forward table. I don't use the front table as I have made a trash bag holder that is velcrowed on the forward side of the sink cabinet.
If I have the drivers seat turned around, I will step on it, then the stove cabinet, then pull myself up onto the bunk using the bunk for leverage. As I weigh 230 lbs and have had no problem, I wouldn't imagine many other people would. If the drivers seat is still in driving position, I will use the wheel well behind the drivers seat as the first step.
Getting turned around to sleep up there with two adults is another story, can be a little tricky.
The only VW van I ever had that was good for upper-deck adult sleeping was a non-Westy '69 that had another brand of camper conversion. Its full roof lifted straight up about 5 feet, and the bunk was a canvas cot suitable, unfortunately, only for single-person sleeping.
After many years and many Westies, my wife and I still haven't decided if the upstairs is intended for adults. When we climb up we do it by taking a big step up onto the closed sink cabinet...I cannot imagine what other option exists.
With the Vanagon Westy (freshly repowered with a Jetta motor, I hasten to interject) we usually wind up on the bottom bunk to be able to see out the windows. Happy camping!
83.5 Westy with Jetta power
92 GTI 8V bone stock
Well, on our 76 DeLuxe Westy, we simply use the cute little wooden garbage box with the plaid, padded hinged top as a step up to the top of the sink. I always thought that's one of the reasons they made the garbage box. The passenger seat swiveled around makes a good first step also.
Depends on how much you want to spend. The step is the easiest, but I always thought a ladder would be cool too. If you look at the side of most fire trucks, they carry a ladder that collapses or more specifically folds. The sides remain parralel to each other, but the rungs move from perpendicular to the sides to parralel when closed (kind of hard to explain, but really simple when you see it). You could make one out of aluminum and then store it on your roof rack etc. when not in use.
I went to my local RV dealer and bought a 6 foot Aluminum. The ladder has rubber feet so as not to damage the floor. I carry the ladder on top of the stove. I use bunge cords to hold it down. At camp just take it outside until bed time. It perfect for that early morning climb down.
Our first parts order after buying our Westy last month included the GoWesty folding stool that we stow folded behind the driver's seat, and it has proven very handy. When camped it stands outside the door to assist entry/exit and we bring it in at night where it lives on the floor in the nook behind the driver's seat in front of the sink.
Come bedtime, the drill is to face the front of the van, step on the stool with the right foot, then step with the left on the front table brace and boost up to the upper bunk. Reverse to get down. I may put some skateboard grip tape on the table brace for improved grip.
I don't ever sleep up there, but when I need to get up there I step on the passenger side seat pedestal then onto the sink/stove cabinet. I've usually got a milk crate with me too that I can use if needed.
As we have gotten older the challenge of accessing the upper bunk in our '82 diesel Westy reached the point where at times it was no longer fun. As luck would have it, about the same time GoWesty had a sale on their ladder. It's a good product - powder coated tubing that (when not in use) is hinged to fold up to fit either in the hole at the rear of the upper mattress (behind the folded over front portion) or directly over head, with the ends resting on the sides of the camper cutout in the roof. It's strong enough to support us easily, stores in otherwise unused space, and works great for us.