You have to remove "doghouse" and work from rear of engine.
Loosen tensioner on AC compressor and alternator then work old belt (s) off. I have 33 ft LY with 454 P-30 chassis.
Mine has serpentine with dual belts for steering / brake pump that run up to AC.
Total of four belts on my unit. I do not have smog pump although it appears as though the unit may have had it at one time.
Careful not to lean on AC refrigerant lines when you are leaning forward into engine and chaffing you belly on the engine. I did and cost me AC line and new refrigerant.
You can reach through fan shroud from rear and work belt off over the fan. reverse process for installing new belt (s). This is even more fun when the engine is hot and you are replacing clutch fan in parking lot of "Autozone parts house". Listen up to earlier post and change out 60 dollar clutch fan while engine is cool and in your driveway. cheap insurance against a certain overheat scenario. Been there done that....
You can replace fan clutch from behind engine but much belly chaffing going on.