The depictions of the BFR for earth to earth travel include the 1st stage booster. I would think if you are just going ballistic, the upper stage would have enough delta V to go it alone, for closer destinations at least. That would simplify the operation a lot. Can anyone calculate the range it would have as a single stage to not-quite-orbit passenger vehicle?
Will be starting with a full-scale Ship doing short hops of a few hundred kilometers altitude and lateral distance. Those are fairly easy on the vehicle, as no heat shield is needed, we can have a large amount of reserve propellant and don't need the high area ratio, deep space Raptor engines.
Next step will be doing orbital velocity Ship flights, which will need all of the above. Worth noting that BFS is capable of reaching orbit by itself with low payload, but having the BF Booster increases payload by more than an order of magnitude. Earth is the wrong planet for single stage to orbit. No problemo on Mars.
The "vacuum" or high area ratio Raptors can operate at full thrust at sea level. Not recommended.
So for testing purposes even longer hops should be possible if they plan orbital launches for it. Maybe they will produce "for testing" vac nozzles which will be safer to use at sea level?
Let's see if this is even possible. There are 3 engines on the upper stage of the BFR that are rated for atmospheric. Each engine, at ground level, has about 3 MN of thrust. The fully loaded weight is about 1335 tons. Gravity is pulling on that mass at a force of about 12 MN.
Bottom line, the second stage can't lift off of the ground fully fueled. It could lift off if it doesn't have a full fuel load, but that would severely limit the range.