Well, if you like tinkering then you will have plenty to do on the V20 to customize it. Ventisit thickness, layers of adhesive backed foam padding if you want more comfort or to change your head height, standard or adjustable headrest bars, bottle locations (behind the head, under the boom, under the seat) for speed and/or accessibility, hydration options (bottle or bladder), bottle cage types, mirrors, lights and mounts on the bike or helmet, camera mounts on the bike or helmet, head rest type (stock or customized) helmet and visor, bar type, shifter type, tailbox type.... there is plenty to keep you busy.
Too comfortable is an issue. I got "Aero is King" stuck in my head lately and while making my V20 as comfortable and aero as possible, I think it is safe to say that my training has stalled a bit. Last September I got up to 221 watts average power for 3H:42M which would now put me over 40kph on a flat course with no wind and no drafting, but my CdA must have been so high then that my speed really suffered (34.6kph). Now my CdA is better, but in this endeavor my power has suffered. Not having someone to chase or to chase me during rides has brought out a bit of laziness. So to answer your question, going 38-40kph on my own on 180 watts has been enough to keep me going out and not really complaining much about the speed, so yes. I haven't really been diligent to make myself suffer, and it shows with not many Strava PRs, Top Tens or KOMs lately on my rides.
It is possible to put yourself in the effort hurt locker on a V20c, you just have to stay diligent on it. It may take a bit of time to get your "bent" legs because your torso angle is more than on a DF bike, so you don't get a full range of motion, and if you go with shorter cranks than you have on your roadbike like many do then that might also affect your power output. Aerodynamics is going to trump that but don't let it affect you.
For clothes, some riders go with dedicated cycling clothes, and I even got a link yesterday from a recumbent rider here in Japan. I usually ride with long sleeved rashguard surfing shirts and inexpensive leggings doused in water in Summer. They are shiny and tight so they probably don't hurt me much aerodynamically. Cycling jerseys and shirts often have pockets in the wrong places for bent riders. Here is the link, but I have never ordered anything from it.
I think DF cycling training plans will work with recumbents. You'll probably find that your mileage is going to increase over your DF because the V20c is simply so efficient.
Thanks for the fueling stuff. I always have plenty of hydration for my rides but fueling for them has been my nemesis. It's funny because I always view food simply as fuel, but I really suck at fueling for my rides. I don't know if bents cause more cramping, but I suck at it probably because on my DF my hard rides were almost never over 100km so whatever I had in my gut would get me through it. Since 100km is pretty easy on a V20 I get into trouble at about 120-150km.
Anyone else please feel free to jump in and share your wisdom and expertise. I just try to keep my stuff simple. Food? Yes, need some of that. Training? Yes, push hard until you can't anymore. Slow down for a bit and then repeat after recovery