Is replacing an oil pan in a 2004 toyota camry an easy fix ?

It isn't too hard. You need to drain the oil first ( make sure to change the gasket around the plug every time you remove and replace the plug or it will leak), then drop the oil pan... put down lots of absorber pads as there will be droppings. Have a rag on hand for your hands. Scrape and clean the old seal where the oil pan meets the engine then put on a new one once it is thoroughly cleaned. Put on new pan, or repair old one.... again make sure to replace oil pan gasket and new oil drain gasket ( around plug..) since your going that far get a new oil filter also.... fill the new filter with oil before installing, fill up the engine with new oil..ps. It takes a few minutes to run down so wait between oil bottles and check the level ( don't run the car) fill the oil until the dip stick reads full ( remember wait a few minutes between each liter of oil to give it a chance to leak into the bottom of the engine). I believe it is around 4.5 quarts including the amount needed to fill the filter.