Mounting /home read-write
Allowing LXD to remap your user ID

The first step for that is to allow LXD to remap your user ID. Remember, LXD uses linux namespaces to isolate processes, and by default even root is not allowed to reuse UIDs from the host inside containers.

We want to allow the LXD demon (running as root) to remap our host's user ID inside a container:

Note: $UID is likely to be 1000 on an Ubuntu system if you're the only user.

echo "root:$UID:1" | sudo tee -a /etc/subuid /etc/subgid

This is a one time step, you'll never need to do this again on your host.
Remapping your user ID inside the container

Once LXD is allowed to remap your UID, we need to actually tell it to do it on a per-container basis:

lxd init ubuntu-daily:z remapped
lxc config set remapped raw.idmap "both $UID 1000"

There is a little bit of magic-looking syntax there, but "both $UID 1000" simply means "map both the UID and the GID, from the host's $UID to the guest's 1000".

We could instead set "uid $UID 1000" and "gid $(id -g) 1000" to be more explicit, but the "both" syntax is convenient.

1) enter copy mode using Control+b [
2) navigate to beginning of text, you want to select and hit Control+Space
3) move around using arrow keys to select region
4) when you reach end of region simply hit Alt+w to copy the region
5) now Control+b ] will paste the selection

you can navigate the text using the emacs style navigation key
Control+p, Control+n, Control+f, Control+b etc.

Dan in the comments informs me that if you have vi style key bindings on then the following applies:

1) enter copy mode using Control+b [
2) navigate to beginning of text, you want to select and hit Space
3) move around using arrow keys to select region
4) when you reach end of region simply hit Enter to copy the region
5) now Control+b ] will paste the selection

To enable vi like cursor movement in copy mode put the following in your ~/.tmux.conf:
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set-window-option -g mode-keys vi

more over what ever you copy, you may dump that out in your terminal using
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tmux show-buffer

and even save to a file(say, foo.txt) using
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tmux save-buffer foo.txt

To see all the paste buffers try Control + b #. To dump out the varios buffers on to the terminal or file you may use
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2
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tmux list-buffers
tmux show-buffer -b n
tmux save-buffer -b n foo.txt

where n is the index of the paste buffer.