Your Ford owner's guide lists the fuses in the "Roadside Emergencies" section.
On our 2010 year model chassis there are actually some unused fuses in the fuse panel under the dash. It's full of fuses and some of them are noted "Not used (spare)"
Be aware that there are several different physical size fuses of the same amperage - mini, standard, and maxi. You may have enough spares under the dash but those spares may not fit in the fuse box under the hood.
Don't forget the fuses in the coach's power distribution panel, in the battery control center (beside the steps?), the in-line fuse for the LP/CO alarm (remove the alarm - it's on the wire). Also, there may be fuses on your 120 volt AC to 12 volt DC convertor.
2011 Sunseeker 3100
1997 Pathfinder Toad