First Extract Batch

So I am jumping into brewing feet first. Here is my story....
I have brewed extract batches in the past with friends (more like watched while they did everything). And I have brewed an all grain batch with another friend(this was very informative). I am reading How to Brew by Palmer and I am going to be taking my first stab at extract brewing this week.

So after searching on craigslist I was able to find most of the stuff to start all grain brewing as well (it was pretty cheap). List of stuff:
Keggle with welded valve and screen.
Brinkmann Burner Link
Immersion Chiller
40qt mashtun with piping
Carboys (6.5gal, 5gal, and 2x3gal )
tons of extras (hydrometer, thermometer, hop bags, airlocks, tubing...)

So here is my question...

1) Should I start with brewing on the stove in a 20qt pot that I have or should I try to use the keggle outside? I am just afraid that the keggle may be to big for my first extract batch.

2) Is there anything else you think I may need?

3) How long should I stick with extract before trying my hand at all grain?

Thanks

1) - The 20 qt pot will work fine for a partial boil which you will end up topping off when you put it into the primary fermenter. The keggle would work fine and it would allow you to do a full boil which is normally preferred.

2) - You are going to need some ingredients.

3) - Stick with extract until you are comfortable with your process and have a complete understanding of the mashing process by introducing specialty grains through Partial Mash brewing. You'll know when you are ready and realize it really isn't that big of a leap to go AG once you have the equipment which it appears you have.

Thanks for the insight... I actually forgot to mention that I bought a Red Ale kit over the weekend as well, Just ran out of time to brew it.