On my GT5 31L5 the drains and overflow run thru the compartment just in front of the wheels -passenger side and extend about 4 inches below the compartment. They are covered inside the compartment with a black hat shaped plastic.
The overflow has a screen cover on the end. The low point and fresh water tank has plugs.
I attached to both lines and extended to the exterior edge of the M H. with cut offs. Other wise you will get wet taking out the plugs.
After doing this I found the lines ran thru the compartment. The best way is to take the cover off the lines inside the compartment, put in-line cut offs. They will be easy to reach and you won't get wet.
2019 GT5 31L5F, 2014 Wrangler Unlimited
CHF rear, CHF front, Sumo springs front