The "losing memory" issue of Radio 10 is usually triggered by the battery being low. This happened to me for a while before I started having odd issues with the car (flickering lights, radio shut off during a shift, then car wouldn't start...)
If the radio detects the voltage is too low when it's in it's "sleep-mode" it will turn itself off and cold start next time. A cold start can take up to 5 minutes if you have MP3 CDs loaded in all 6 slots.
Check your battery level. I'd bet you're near the lower side. If so, I'd advise you trickle charge it over night before your trip. (And take the charger with you, with a long extension cord, just in case.

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