Here is an alternative battery solution that is pretty inexpensive. This is Costco's (made by Interstate) biggest battery- the 27DC. It's a dual purpose battery- Starting and Deep Cycle and it's a beast!
Less than $90 at Costco.
I've been running this battery in my boat for a few years now and I'm very happy with it. I can run my trolling motor 8+ hours and still have plenty of juice. I've fished at night and had the deck lights (non-LED) on all night too. In fact, I've
never completely discharged this battery.
Along with 750 cranking amps, it has 160 minutes reserve capacity.
Reserve Capacity is a very important rating. This is the number of minutes a fully charged battery at 80 ° F will discharge 25 amps until the battery drops below 10.5 volts. 160 is a good number- Perfect for camping.
Problem is, the terminals are on the wrong side to be used in the 4Runner.
I made it work with all the factory cables. Only thing I made was an extension strap for the positive terminal. A few things had to be modified a little bit though. Read on...
**Starting with the negative terminal, I flattened it out and oriented the clamp like you see. The cable fits
between the battery and the tie-down rod. I also re-routed the cable so it was under the feed for the fuse box (pic). The ground strap on the fire wall also needed to be removed and reinstalled (no modification to it, just needed it temporarily out of the way).
The only other thing I did was to pull the main wire loom's plastic retainer off the steel bracket (right next to the alternator) and strap tie it as shown. Where the negative terminal exits the wire loom I cut a little bit of the electrical tape away.
These slight changes allowed the factory cable to fit with no stress.
**Now, the positive terminal.
There are 3 parts we are dealing with here:
The battery clamp, the starter cable and the feed to the fusebox.
The lug on the starter cable was flattened just like the negative battery lug. I drilled a second hole in this lug directly behind the first. This was so I could attach an extension and not worry about it turning or loosening up.
The extension is basically a piece of steel 4" long by 3/4" wide with 3 holes; 2 on one end for the battery clamp/starter lug, and 1 on the other for the fusebox lug. This extension is needed to connect the fusebox wire to the battery because that wire is too short to reach.
The starter cable connects at the battery clamp (like it originally was) with the extension bolted on top with 2 bolts. At the other end of the extension is the factory fuse box feed on top with my Blue Seas fusebox feed underneath. (The Blue Seas wire is the one in the picture that runs next to the factory fusebox.)
I used galvanized bolts and locknuts to connect the extension. Then I coated it all with liquid electrical tape for insulation.
The pictures look a little rough, but that's because I was ran out of liquid electrical tape, LOL. I'll make it all purty tomorrow. It's strong and tidy. I doubt I'll have any issues with it!
It fits in there really well now with zero stress on the wires.
***
P.S.
I did a test run tonight. My 1000 watt inverter would not run my camping coffee maker (Mr Coffee 5 cup mini 750W) without the truck running. I made two back to back runs
with the truck off with no problems. What's even better is I used the battery fishing today, so it wasn't even fully charged!

Me likey.
Happy modding!
EDIT- I fixed this half-assed crap the next day. LOL! Scroll down a bit...