When I do a formal training cycle ramping the load over a period of time, 2 days off (usually Monday and Friday) has been typical protocol on the plans I've followed, with an easier week built in every few weeks. I found good results.
The last part about easier weeks isn't really needed if you are on a steady riding schedule, but you'll hear folks who ramp the workload over a period of a few weeks or a couple months, like during a build cycle, talk about "digging a hole". There are three components to how strong one is on a bike at any given time: Fitness, Fatigue, and Form. Fitness is the amount of work we are doing, but as we work fatigue increases as well. The key to being strong at run time, i.e. in good form, is resting just enough so that fatigue subsides somewhat, but fitness doesn't diminish significantly. So, the bigger the hole, the more recovery needed to find good form.
Here are two examples, one is a short cycle showing 3 days on the bike, then one day of rest. You can see fitness, or workload (represented by the charts bars) causes fatigue to rise, and form to drop. Form rises, and fatigue drops following easier days. Ok, I think we all pretty much know about this relationship:
Small holes can be dug for 2 or 3 days (even one day can dig a tiny hole, but probably only good enough to plant a shrub), big holes can be dug over 2 or 3 months.
Here is a much longer cycle of an athlete digging a serious hole, steadily increasing the load over a couple months. The riders
fatigue (purple line) rises along with the riders increasing
fitness (blue line). Then, significantly reducing the work, known as "tapering" sees a spike in
form (where the orange line crosses the blue)... that is the period of time to target a major event:
It is important to note that this longer cycle of digging a deep hole will have built in rest days each week of this progression, and the rider will feel as they are generally improving, but it is not likely that the rider will ever feel really fresh or his strongest during this build. There will be periods of respite every 3 or 4 weeks where the rider will emerge with new spirit, but with it the knowledge that another period of being beaten down is about to begin. The joy! And there will be a time toward the end before the final reduction in workload where the rider will probably feel quite exhausted. But at the end, this rider will emerge feeling like a superhero ready to crush his enemies, see them driven before him, and hear the lamentation of their women!
At two days off you are finding the following ride easier because your fatigue is low, and form is good, but your fitness is probably pretty low as well (relatively speaking). That's not necessarily a bad thing, it all just depends on your goals.
The amount of rest needed could vary based on age, the amount of quality sleep one gets (say 8 hours compared to 5-6 hours), diet, and personal constitution, but at least 4 or 5 days a week is needed imo to show improvement and reach one's full potential. Don't get me wrong 3 or 4 days a week on the bike will keep one basically fit, but you'll lag behind the guys putting in longer/harder miles (i.e who dig bigger holes) when they decide to get frisky.
As far as refueling I find I do way better (feel better during the following days ride) if I have some liquid carbo replenishment within the first 30 minutes of getting off the bike following a particularly grueling or high intensity ride, and especially if my legs feel cooked. Better some sort of sport drink, but a can of soda will do fine. Then a shower, followed by a nice big dinner (or lunch)!