Well I'd use a additional TV with built in DVD player more than likely, but..
Odds depending on your answer to Some questions:
IN the RV are there two TV's (or more) IF so odds are the outside socket is fed by the same feed as the REMOTE TV (The one farthest fromn the source selector switch That may be just a wall plate with a switch?
2: Do you have a Single Source switch (the wall plate) or a matrix Swtich (Box of many buttons). Odds are with the BOMB the otside TFV is "TV-3" if you have onem else TV-2 (along with the remote TV)
3: DO you CHANGE inputs on your main TV when watching a DVD (May not matter) or do you watch on Channel 3/4.
IF you MUST change to either A/V in or HDMI in then your odds of watching the inside DVD player on an outside tv just went DOWN!!!!!! like next to zero without modification)
Advise
Modifications:
For DVD only, a simply RF modulator can be wired up, along perhaps with an A/B switch .. (Note this is built into the BOMB) on the wall plate with the plate OFF the wall looking at the rear cables down
1(ANT) do not mess.. 2(Park cable) 3:TV-2
If you want to be able to watch a DVD outside while darling spouse watches something else inside, remove the cable from TV-2 and hook it to the COMMON (Switched) lead on the A/B switch, A goes to the port just disconnected from. B to the RF Modulator's RF out (DVD's are Binary).
if you only want to watch the same program on ALL tv's then disconnect from the CENTER (Park Cable) and run a jumper from there to the Switch common,
A gets the cable just disconnected and B again the line from the RF modulator.
IF you have a BLUE RAY (HDMI out) procedure is the same, Modulator more expensive.