If it is just a toy then you don't wanted too much hardcore racer stuff then.... If you drive her on the freeway I would go with 3.55 or 3.73 gear,4.10 is a lots of gear if later down the road you really gets into the sports and wanted to put in a Supercharger/Turbo etc.( The first time that Honda smokes you at the stoplight ) Take a look around the forum and just about everyone have upgraded their shock and struts by now,anything out there in the aftermarket is superior to the factory stuffs. You might like the looks and the better handling of your Mustang if you lower it with some aftermarket springs. A stock AOD Mustang with 3.08 gear and converter is a dog. I would replaced the converter with a aftermarket unit ( B & M 2400 Holeshort,Edge ,TCI are just a few brand that cater to the AOD crowd ) with a stall speed of around 2400-2600 max. A aftermarket valve body or shift kit ( Lentech, B & M etc ),with the addition of the higher rear end ratio your car will feel like it just lose a thousand pounds of dead weight. All this with out even getting into the engine. A lot have been publish about switching over to the 5 lugs setup for cheap ( Ranger axles etc ) and aftermarket company sell the whole rear disc brake for the Fox Mustang. A better set of Brake pads ( Front and Rear ),Steel braided brake lines from Russell or Earl's will do wonder for the feel and braking distance if fund are running low ( The aftermarket lines could still be used on the new disc setup later down the road ).
Have fun in exploring the endless world of the 5.0 Mustang.