Building your vehicles will be a personal choice, but here are some things I found useful.

Use nylon standoffs and nuts and bolts where electrical components mount to metal.

Clean and repaint any old Meccano to remove the lead paint.  A quick hot soak and rough scrub will remove the paint and a respray will have the parts looking marvelous.  

Meccanoid headsets require a library with iffy hacks.  I added values to the variables with empty [ ]'s to make it work.  A different mount and lights might be prudent.

A 3d printer is an awesome accessory.

Mecanum wheels of my design use 160 nuts and 32 bolts

Stereopi's can be bought in Canada at the Pishop.ca

An Esp32 devkit is much more useful with an adapter board.

Power banks that have an on/off switch are nicer to work with.  12 volt power banks with 5 volt USB outputs are especially handy.  3 amp minimum capacity.

When getting your mecanum wheels set up, do one at a time to check forward and back and which way they should be turning on spins.  Change the pin numbers in the software, do not move the wires in the motor driver.

L9110S motor drivers can be used to control speed and direction, many advertise them as only being direction control.  I like the double version for the mecanum wheels.

Many things left to do:  

Needs some finishing touches.

Need a way to switch over to a third camera for backup purposes on the wheeled unit and  to determine whether an Access Point will still be feasbile.

Need to smooth Perky's neck, currently it is just jumping 15 at a time.

Mecanum vehicle needs some more tricks.  The joystick should be redone for ranges and with methods to do pivots and diagonal sidling.

et cetra

My software has no warranty and probably shouldn't, but does kinda work lol.

Have fun with this, a project that everyone who has tried it so far is enthused about.