Step 1: Acquire the barrels
I shopped Craigslist and got lucky - found a guy that lived close to me who liberated them from his workplace - $15 each. One had peaches the other apricots - my yard has a new aroma.
Step 2: Barrel Orientation
Since these were "closed lid" barrels I decided to go with an upside down setup for several reasons.
My thinking was that I just didn't trust the thickness of the sidewall for a tap in connection since I wouldn't be able to thread a nut on the backside, so I went with a connection into the bung plug, thus needed an upside down orientation.
This provides for the barrel to be completely emptied, unlike most with a side spiggot - but also required me to build the base platform to elevate them slightly for the plumbing.
Since they store on a second story I had no issues of elevation to accommodate a watering can either so the base was fairly routine to build as opposed to one 2' tall.
Step 3: Platform/Base
The barrels measure 23" around so a precut 2' X 4' of pressure treated 3/4" plywood was used as the base with 8 2-1/2" 4 X 4's scattered around underneath as feet. I Painted with deck paint for extended durability.
Step 4: Downspout Gutter Connection
I removed about 5' of the existing downspout and reconfigured the angle with a new piece to aim it toward the barrel instead. I then used a piece of flex-gutter for the final connection to the barrel.
Step 5: Barrel Input Connection
The cotter pins, wire, & wire tie hold the flex tube into the mouth of the filter - in case a heavy ran might try and disloge it from the filter due to back-pressure.