Can Muffle + Invisibility replace Sneak?

[Silk Zither]

I'm building an arcane archer with illusion and conjuration. I don't want to sneak like a gutter rat, but I don't want to deal problems mindlessly head on either. I do like scouting out a place, plan my attacks, and not be caught off-guard. From what I understand, detection is determined by sound and sight. Does that mean if I have 100% muffle from either the spell or a self enchanted gear, and then drink an invisibility potion, I no longer need to Sneak (crouch) to avoid detection? Or does muffle and invisibility only come into effect when you're crouching in sneak mode?

 

[Silk Zither]

Since nobody bothered replying, I tested it out myself. Finally reached the minimum skill level of 25 to cast muffle today. So far, the theory works on most. I cast muffle, then drank an invisibility potion, and danced around giants, bandits and guards, they didn't notice a thing! Even took awhile for them to find me after I bumped into them. And if you keep a distance, they eventually lose you.

So far, the only npc that's noticed something strange is a master vampire. I went into Haemar's Cave on my way to the Grey Beards, and non of the vampires noticed me until I got within a few metres of the master vampire, he said "something's not right" and they all started searching for me. However, when I tried the same thing with sneak mode on, he didn't notice a thing even though I was crouching right under his eyes. (btw, my sneak skill level is 16, lol.)

Also, for some reason mammoths just seem to notice if you get too close, no matter what; no idea why they possess such intelligence. Has anyone actually succeeded in getting close enough to one of these beasts for a sneak dagger attack?

 

[Lizardking1]

Thing is, doing those things while crouching will boost your Sneak. As far as I know Sneak increases when you're crouching near an NPC and not being detected. So what you're doing isn't an alternative, but a training program =)
No I never sneaked up on a mammoth. It's much funnier to make them fight each other.