I would control my pace, keep an eye on HR (if it climbs much above about 130 when walking, you might wish to slow or pause). You can push it later when you 'know' or feel it in your bones that you're ready for a greater effort. That may be a month from now. Also, keep an eye on electrolytes if you're going to be sweating some, and of course keep the fluids up. Also, keep a snack with some carbs so you don't 'bonk' and maybe encourage a cranky heart.