You are on an IFR flight plan so IFR rules apply.
A SID is exactly what it says. A STANDARD instrument departure.
If they clear you via a non standard instrument departure you have to comply with IFR obstacle clearance limits yourself.
There are a few things you can use.
Close to the airport you could use circling minima as a reference.
Next thing to look at is the Instr App on the side you are climbing.
Minimun vectoring altitudes are also an option.
The the MSA can be of some value.
If you know your rate of climb and average ground speed you will have a good idea where you will be and at what altitude.
Other option is to simply refuse the clearance.