Snook -
Congratulations!
I have a '99 and have had a lot of practice with installing car seats (had 3 to date).
For the 4Runner (and IMO) all vehicles the best place to install the seat is in the center of the back seat. Many, many people put it one one side or the other for their convenience.
Use the lap belt for the base and don't worry about not having LATCH.
The best technique I found is to sit on your knees on the seat/base with all your weight and pull, bounce and rock the seat, pulling hard and getting it tighter with each bounce. The base/seat should move less than 1" max.
We found getting Brita brand seats is better since they last longer (larger weight/height). Will save you the cost of 1 seat.
I recommend a mirror that goes on the outside headrest so you can see her. Use a rolled up blanket between the mirror and the headrest to get the angle right.
My son is 3 and is still in the middle, facing forward. It gives you a place to sit inside the car if it is raining or cold.
Hope this helps.