Heater core 99 GMC Suburban

[Birdmann604]

Yesterday noticed anti-freeze type smell inside suburban while driving. Carpet on front passenger side wet. I want to confirm my suspicion that it is a heater core gone bad or hoses to/from it. I'd like to know how-to fix it (replace) & degree of ease/difficulty of that project. Thx.

[YukonGMC]

Sounds like a heater core to me. Major job.