In your rommon example you are using 192.168.20.0 network. In your running-config example you say you want to use 192.168.1.1. If you do that then, yes, you will need a route off that subnet to get to destiantions on 192.168.20.0.
Well all your physical interfaces are all shutdown (and not assigned to any VLAN). That will certainly prevent you from reaching anything via any of them.
I'd suggest you give your VLAN 1 a nameif (e.g. "Inside") and assign your switch port(s) to the vlan as access ports do a "no shutdown" on the interface your PC is attached to. That's pretty much textbook from the configuration guide (here).
Other than that, you shouldn't need a route statement as your PC is on the same subnet as the vlan 1 logical interface
In order to place ASA code back on the device (or any other desired file really), it has to be done via ROMMON utilizing TFTP, as you already did. Once that is complete, you have booted from the file but the file is not saved to the persistent memory so if you reboot, you lose the data.
The process is simple, once the asa code has loaded, you need to configure a basic route, in order to communicate on the network so that you can download a file via ftp/tftp. I like to format disk0: (flash:) before beginning, to ensure we start with a clean slate. Then you would need to go onto your Management port (1/1 or 0/0 depending on ASA model)
Configure an IP address and a subnet mask correspondent to your network. Then, like Marvin stated, you name the interface (nameif) with something like "inside" and configure a deefault route, something like:
route inside 0.0.0.0 0.0.0.0 <Gateway IP Address>
and make sure you run a no shut on the management port as well. That is pretty much everything. Then you should be able to move your files using your FTP/TFTP servers.
We are pleased to announce availability of Beta software for 16.6.3. 16.6.3 will be the second rebuild on the 16.6 release train targeted towards Catalyst 9500/9400/9300/3850/3650 switching platforms. We are looking for early feedback from custome...