Cruise Control & Seat Height Solutions ?
Have you considered used parts from Beemer Boneyard.
You'll need to be patient.
Used Throttle Meister units are available for $75-$100 and up
depending on condition.
As for the seat height issue,
many different height seats are available from BMW.
Taller riders will get rid of a low seat
in favor of a tall comfort seat.
A used/salvaged LOW seat for the Roadster may start at $150 and up
depending upon whether torn, stained, or discolored.
Try a used LOW seat for a while, and if the height suits you better,
you could have it recovered in a nice leather.
fyi,
Your problem is not uncommon.
In Japan, many riders are "vertically challenged"
regardless of being male or female.
In fact, my Japanese BMW dealer informed me
that ALL his new Classic version bikes
came equipped with a LOW seat.
Lowered bikes are gaining popularity here rapidly.
Having the dealer lower the machine is always a $$$ last resort.
Other bike forums and message boards allow classified listings
for BMW Roadster parts, also.
You may choose to search there.
Checking the oil level ?
Hmmm........
Dipstick on a Roadster might be a challenge.
I used to park my dirt bike against a tree
because it had no side stand.
A board or other spacer under the side stand is easy and cheap.
I have parked my R1100R up against a wall, left in gear,
to remove and grease the center stand.
The bike had plastic engine guards and side bags. No problem.
You could use a towel pad for the bar end.
The oil level sight glass should be visible on the left.
Try and keep the bike as level as possible.
The oil level sight glass is a very rough estimate, anyway.
From bottom to top of the fill circle is about 500cc of oil.
A hydraulic bike stand that lifts it up
from below the engine sump is another solution,
although rather expensive.
BMW makes a shop stand to keep it vertical, also.
Probably somewhat less $.
Good luck.
Keep 'er shiny side up!