If your home has a 4 prong 30 amp 240 VAC Dryer Outlet then NEMA 14-30P to NEMA 14-50R adapters are available to safely adapt that to a 50 Amp RV shore cable. You can also get a NEMA 14-30P to NEMA TT-30R adapter to safely adapt to a 30 AMP RV shore cable. Both are available on Amazon.com and other places.
However, if your home has a 3 prong 30 amp 240 VAC Dryer Outlet then this can't be safely done without having an electrician change the dryer outlet to 4 prong. This can only be done IF the wiring from the breaker box to the dryer outlet has separate Neutral and Ground wires.
Starting in 2000, the 4 prong outlet and the wiring with separate neutral and ground became required. Before that, no. So if your home pre-dates 2000, then the 3 prong to 4 prong dryer outlet conversion may require a new wire run from the breaker box to the dryer outlet.
If wiring from scratch, just do it right and put in a NEMA 14-50R on a 50 amp 240 volt double breaker, or put in a NEMA TT-30R on a single 120 volt breaker.
Randy - Manhattan, Kansas
2015 Vista 27N
2016 Honda HR-V