I recently completed the Grafton to Inverell road race with the majority of the prep being on TR indoors and wanted to post it as a reference for others (i wasnt sure going in if the volume would be enough given how long the race is). For context, Grafton to Inverell is a 228km road race in Australia with ~ 3500m of climbing including a 950m HC climb at 80km.
I completed a high volume SS base , with about half of my volume being outside over summer. I was doing 2-3 indoor 2 hour sweet sport rides/week and 2-3 outdoor rides ~ 100km to 120km in length a week. I then switched to mainly indoor due to work and family commitments from late January. I did the sustained power build and the climbing road race speciality plan following them completely. I was doing a long 4 hour ride outside on Sunday only. This was giving me around 600 to 700TSS a week.
I did a 190km practice ride 6 weeks out to test nutrition and pacing. I then crashed a couple of days later (with some surgery which i am sure lost some fitness). It also meant i was pretty much only on the trainer for the remaining weeks of prep.
My final FTP was 4.38 w/kg and i did Div 3 (ie Cat 3). In the race itself, i was pretty comfortable for the first 80km before the main climb and the sweet sport work really helped get up the climb with the front bunch. The remaining 130 km after the climb consisted of lots of 2-5min hills which the plans really helped for. i flatted with 70km to go and had enough in the tank to chase back to the bunch for 15min. The plan also gave me the legs for the last 50km which switched to lots of attacks and normal race pace for a sprint at the end.