Good work there mate!
My seal slowly started to leak at around 105 000km doing the Ruta 40 in Argentina. But from a curiosity I wanted to try replacing the bearing as well doing it in the "bush".
And as you already know it is actually very easy to do if you know how to do it by using heat both on removal and on installation of the new bearing. I also used my camping stove (you can use hot exhaust while bike running on center-stand as an alternative! and use your motorcycle gloves to operate with the hot bits).
I always crarry main bearing and seal with me - even BMW-original costs less than a chain+sprocket set, weights times less to carry it with you.
But your 35K Mi bearing failure smells like a bad shimming to me unless you do extreme offroad or load the bike constantly to carry over 500kg. Re-check your bearing preload (shimming) before you do your next big trip!
Mine went well over 60K miles before any sign of bearing wearing out (metal bits in the oil is the first warning sign) and I mostly travel on bad potholed roads, occasionally technical offroad bits and this is all the time with fully loaded bike 2up, places where most people would not dare to go 2up.
Main bevel box bearing should go well over 50K miles when shimmed close to perfect (max +/-0.10mm off the spec). Over 100K when shimmed perfect even if abused with constant offroad and high loads (like mine is).
Ride safe, Margus