After 20' warm-up, ride a rolling course, 2x the following (40' at IM HR/ and 20' at Half IM HR). Half IM HR should be about Zone 3 and IM HR are Zone 2. Stay consistent and go right into the run when done.
Run 60' on a flat course or treadmill after bike workout. Keep HR in Zone 1-2. Stretch when done and add in Core 1, 2 or 3.
WU: After 300 warm up, swim 8x50 on 20" rest.
MS: 100/200/300/400/500/500 all with 10-20” rest. Last 500 should be ~3-5” faster per 100, than goal IM Pace. For example, if the goal is 1:00 swim at IM - that would be 1:25/per 100/yd pace. So, the goal in the last 500 of this 2k set would be under 6:50 or 1:20-1:23 pace.
CD: Get a nice easy 300 cool down.