This is what I'm talking about. Noted trainer Bret Contreras is recommended one set of five different exercises, five days a week. Because the reps are higher, there is no need for a specific warmup. Add in a little walking. Maybe a day or two of something more vigorous. You're good to go:
http://www.bretcontreras.com
Note: it is not true that "Studies show that multiple sets are superior to a single set." A rather large compilation of such studies have only a handful of studies showing a marginal advantage, with all others being muddled. Therefore, if there is little or no evidence of such an advantage, why do more than one set, unless of course you prefer to pace yourself ?