99 Blazer hard to start at any temperature, aggravated by cold

Ya, lot of miles, depending on the shape of the vehicle, you have to ask yourself is it worth it? One thing on the fuel issue is you should check the fuel pressure by hooking up to the Schrader valve, and get the fuel system up to pressure (56 to 63 psi) and let it sit for 3 minutes. The pressure should not drop more than 5 psi from the initial pressure. In other words, start the engine and see what the pressure is, then turn it off and let it sit for the 3 minutes. If it drops more than the 5 psi, you would have a leak from a bad regulator, injector, or spider lines. Common... And if so it is recommended to replace all which is quite spendy. You can replace individual components but there is not much luck in doing so. You would be right back at it. The 4-wheel drive front axle sounds to me it would need to be taken apart to see what the problem is...