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From your signature line, that year 24V is probably on a Ford chassis? E350 or E450? Original tires are probably 225/75R16. Is the coach where you can see it? The tire information will be in a sticker on the driver side door frame.
You don't want "P" series tires, the "P" is for "Passenger." They need to be designated "LT" for "Light Truck" and/or carry a "Load Range" of "D" or "E" and today most tires this size are sold in Range "E."
With a 24-foot coach, you won't be at the very max weight for your tires, like our 31-footer is. For that reason, I don't think there's need to pay extra for commercial tires in your size, like Michelin XPS and Bridgestone Duravis R250. A couple very good brands you can shop for are Michelin LTX M/S2 and Firestone Transforce. Chances are you'll need to replace them on age, not wear, and a good brand like that will work for you till the heartbreaking time to replace good-looking tires with plenty of tread left.
In USA, many of us have been very pleased with price and service at Discount Tire. Hopefully our Canadian members can offer names on your side of the border.