I want to install an outlet for outdoor connection of an RV. However, the location of the service entrance box is close to a inside corner of the exterior of the house so the easiest location is on the same external wall as the service box and will require a hole through the brick wall near the service entrance entry conduit. The outlet would have to be in close quarters since the wall is only about 2 feet wide so the entrance conduit goes perpendicular at the center of the wall plus other wires and entries are in the same area. I want to run the outlet wire out through the brick about half way between the conduit and the corner directly into an external surface mounted box with a 120 volt outdoor circuit for utility purposes on a separate wire passed through the same conduit through the 220 box to the 120 box. Is there anything questionable or incorrect about that installation method, or something I should be concerned about with it?
You're on the right track
Since you have a suitable panel, and enough spare space in it, I would go for what you describe, using 3 6AWG wires for the 50A/240V circuit and 2 12AWG wires for the 120V circuit (as well as a 10AWG ground, if you're in plastic conduit that is). You'll want to use a GFCI breaker at the panel for the outdoor 120V circuit, by the way, as that keeps it safe from the weather, vs a GFCI receptacle outside which can get affected by water that leaks into the receptacle box.
If you're going to do this using cables, then you can use 8/3 on a 40A circuit or 6/3 on a 50A circuit for the 240V receptacle, with a 12/2 extending into the 240V receptacle's box and spliced there to some 12/2 UF or two 12AWG THWNs in conduit to connect to the 120V receptacle.