2 - I need to eat at least twice a day. Otherwise I'll be weak therefore I can't run (I hope there's a toggle walk button) and I will only be able to use the main (right) hand. So before I go into the wilderness I must make sure I have enough food with me (or do a Bear Grylls and eat some worms).
3 - I need to sleep at least 6 hours a day if outside or 4 hours in a bed. Otherwise the same rule for starvation applies: I will be too weak to run and I can only use the main (right) hand.
I'm in the military and I can assure you those points aren't all that realistic. Here's some advices I can give you based on field experience :
Just for reference, eating around 2000-3000 calories a day (depending on height and weight) will let you function at full capacity. Hard physical activities all day long would require twice that if you plan on doing this for extended periods. That being said, since you're doing some seriously heavy physical activities in Skyrim (climbing, running, swimming, fighting all day) it does make sense having to eat often. Though, even if you don't eat for a whole day or two, you'll still be able to function more or less normally. Starting on the 3rd day without food, you'll start feeling more and more drained but in most cases, you'll be more mentally exausted than physically. Account that going without sleep increase the amount of calories the body burns.
About sleep, you'd be suprised how long you can go without sleeping. I spent 5 days without a single minute of sleep and was still fully operational when adrenaline kicked in. Again, it's more of a mental exhaustion than a physical one. After few days without sleep, your moral starts to go down drastically and you get irritable and emotionnaly unstable, jumping from depressed to angry in a flash. But, like I said, when the adrenaline kicks in (you're being attacked), you function 100% operational.
Also, normally it's the opposite of what you suggest about sleeping in the wilds. When you're in the wilds, you normally don't sleep much. You have to keep your fire going, you get uncomfortable and cold, there's lot of wild noises and as soon as the sun's up, you wake up, not mentionning having to keep watch when in groups. So, yeah, when out there, you don't sleep much. But then when you come back to civilization and get to sleep in a warm bed, trust me, you can sleep for hours!
Basically, you wouldn't get mentioned penalties as soon or as drastic. I would review them to kick in more late in the process and more gradually. For example, not being able to run because you didn't eat twice that day is kind of harsh. I would say that you'll get no penalties until few days without food. If you get to eat even the tiny littles things here and there, you can probably go for 4-5 days without problem. Considering that there's food everywhere in Skyrim, I'll keep myself to having to eat daily and if you can't you stop focussing on whatever you were doing and start to solely looking for food. You'll probably never have to go as far as getting penalties. Same applies for sleeping. You'll never get tired enought that you couldn't run. There's towns and camps everywhere in TES games.