Tried to answer Chances' question on the high wattage items, keeps timing out on me. For a 1500 watt item for 15 minutes its 375 WH; typical GC-2 battery is 2700 WH. Keeping discharge to 50% is 1350 WH. The drip coffee makers I'm familiar with take about 20 to 30 minutes so figure 750 WH or half your 1350 WH of available battery.
600 watts of solar in the lab is less in real life. This may replace the coffee maker usage in about two hours in full sun. Panel output decreases as air temp goes up.
Here on the East coast it is taking from 10 AM to about 4 PM to make up for our usage over a 24 hour period which is one attic fan and an O2 Cool fan from 10 PM to 5AM plus two of the leds for about 3 hours. Water pump is around 6 amps times about 4 10 second flushes during the night.
This why a usage audit is so important. Check here for Gales' solar and battery sizing spread sheet:
http://w8usa.org/club-library/documents-presentations/
This guy says the same thing as Handy Bob with out the rant:
RV Electrical