Bonneville is a 200 metre wide crater

Thus - it's circumference is around 630 metres.

The heatshield is about 40% of the way around the crater - call is 250 metres.

It's taken more than 60 days (minus the trouble, call it 30 days of travelling) to get from lander to crater, which is a little over 300 metres in itself - and dont forget, the crater rim is very VERY rugged and rockey and they would struggle to increase on 20 - 25 metres per day. - call it a MINIMUM of 10 days to get to it.

After that, you have another 40% of the crater's rim to navigate to get back to the side facing the Eastern hills - so another 250 metres of rugged rockey terrain - another ten days, one short of three weeks

If I were the rover drivers, I would want to spend as few metres as possible driving on the rim, it looks hellish - and even more so when the opportunity to visit Opportunities heatshield is both an easy drive, and one of the only features on route to Endurance Crater

Doug