But welcome to DU Herman and welcome to the bike group. Maybe we can get some action here. Not to judge, maybe all the DU cyclists are busy churning out the miles.

A fucking mazing but you feel like the whole world will run over you.

Have yet to try a recumbant 2 wheeler , .

I'm curious about how they routed the chain around the front wheel and visibility with the pedals, feet, and handlebars and headrest all in a line.

There is the potential for the front wheel in a sharp right turn to hit the chain and/or any tubes surrounding the chain. From what I understand, the chain does have some flexibility in it, and just being tapped by the front wheel might not mean that it falls off the chainring. Moreover, if all this is still viewed as too problematic, one can use tubes and ties to raise the chain higher, permitting the chain to clear the wheel during turning.
There is also the potential for the front wheel to strike the heels of either foot during turns. But this is solvable problem for many recumbents, one simply just foregoes pedaling while turning
With regards to visibility (specifically, seeing down the road), the angle of the seat can be made more vertical I believe, though there are limits here.

It states that the handlebars have four different position options; if they might partially obstruct one's vision, then one could have them at the most horizontal, lowest position. And I do suspect that in the picture the seat is not at its most vertical.

More on the bike:

http://m5ligfietsen.nl/site/EN/Models/Carbon_High_Racer

Curved metal parts tend to absorb some of the shock of hitting a pot hole, not as good as a shock absorber, but is one of the reasons conventional bikes front forks had a slight curve to them.

Notice the curve in these conventional frames:



I bring this up for front forks with shock absorbers, tend to be straight so that the shock can work. Thus a lot of people today have NOT seen a conventional front fork, or if they did, did not notice the curve in such forks.

The distance between the wheels also will help a rider take shocks, again NOT as good as a shock absorber, but does make the ride technically less harsh.

...it's just that I wonder if all that would still be enough. A recumbent rider cannot stand on the pedals if he or she is about to run over a jaw-jarring pothole.
On the other hand, I likely am emphasizing all this too much. Heck, what about all the mountain bikers who have to deal with far more terrible bumps that even their suspension can't make perfectly smooth. Moreover, the M5 High Carbon Racer has been used for the famous yet long Paris-Brest-Paris brevet, as well as lengthy travel on all kinds of conditions on the Silk Road.

Thus the main "Fault" of recumbents are avoided in that ride. Recumbents are faster on the flats then conventional bikes, but slower going up hill (Downhill is about the same for both bikes). By avoiding the mountains, you work with the main advantage of the recumbent.

Now, a recumbent can go uphill, it just that conventional bikes do it better and faster. Thus in the mountains I would avoid a recumbent for the main problem is going uphill, not downhill. On the flats (and that includes most Rails to Trails in the mountains, the old steam locomotives did NOT want to go over a 5% grade, and such a grade is well within the ability of a recumbent) a recumbent comes into its own.

I did like the report in suspension and bicycle that point out that most suspension is a waste of money on the grounds that suspension comes into its own off road NOT on road. The pot holes in most paved roads, when it by a bicycle, are to quick for the suspension to come into operation. Suspension are used to smooth out a lot of bumps not just one bump caused by a pot hole. I live in an area of a lot of pot holes and suspension kicks in AFTER you hit that pot hole. On the other hand, when traveling on a brick road with uneven bricks the suspension comes into its own, the suspension smooths out the ride on that rough road due to its ability to smooth out the many bumps the bike is hitting.

Thus suspensions have a very limited affect on the effect of hitting A pot hole with your bike, suspensions are design to handle a lot of small "potholes" one after another that one runs across on a rough road or path. It is for this reason bikes did not have suspension till off road biking became popular starting in the 1980s.

Even today most road bikes do NOT have suspension, for such suspension is NOT needed if the road is relatively smooth (and that is true even if one is on a dirt road, when you need suspension is on paths and other "unimproved" roads). It is on such rough "roads" that suspension comes into its own, otherwise suspension is a waste of money.

Yes, I agree with much of what you wrote. When I bicycled with a group on my recumbent, they would pass me going up the small hills of Virginia, but I would pass them going down. The main advantage the upright bicyclists had going up a hill is that they could stand and push down on the pedals, whereas I could not. Going down the hills, my recumbent and I were more aerodynamic and thus a bit faster.
As you noted, a recumbent is not completely worthless on hills. I do believe that a recumbent did get up Mount Washington (I believe in New Hampshire) some time ago. There are individual hilly streets of such a high grade that would (I believe) defeat a recumbent but not an upright bike, but this might not matter much, as the cyclist on the upright bike would be going so slowly that the recumbent rider walking his or her bike up the hill might not really be that much behind.
In most circumstances, the recumbent rider should be okay.
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I am thinking about acquiring the m5 simply because over the course of years the 2 recumbents that I have have now reached the point of something or other often going wrong with them. One of them might need a completely new frame.