Yes, it is definitely possible to set up without an internet connection, in fact that's how I use my PS3 with PKG linker everyday via a Direct PC to PS3 Ethernet Cable Connection. You must make sure you are using LAN ip addresses. WAN ip addresses do tend to tend to change alot unless you're paying for a static WAN IP Address, which is usually useful for hosting servers or something else online for others ourside your network to connect to. This isn't what we need for this instance however.
But that's a discussion for another time.
If you're looking for speed, direct ethernet connection would be your best route. It requires editting your NETWORK & INTERNET SETTINGS on Windows to change a few things, and it'll keep you from having to change the IP address on your PKG Linker & PS3 settings all the time.
Make sure the ethernet cable is firmly connected to your PC & PS3
On your PC:
Go to Control Panel
Select Network & Internet
Select Network & Sharing Center
on the left side menu, select Change Adapter Settings
A new window may pop up or in the same window, make sure it says Network Connections
On Network Connections, right-click the one that says Ethernet
(Make sure this is the Ethernet Cable Connection, it may have a red X on it when your PS3 is turned off or on.)
& select Properties
On the Networking tab, select Internet Protocol Version 4 (TCP/IPv4) then click Properties
IP Address: 192.168.0.5 (My PS3's IP)
Subnet Mask: 255.255.255.0
Default gateway: 192.168.0.1
Preferred DNS server: 8.8.8.8
Make sure to input these settings, the IP address must be your PS3's IP address.
This can be found by checking your PS3's internet connection status from the XMB Internet Settings menu.
On PKG LINKER
PC IP: 192.168.0.5 (My PS3's IP)
Use the Ping tool while your PS3 is on to ensure you are using the correct IP address, I am just using mine as an example.
On your PS3
Set up a Manual Internet Connection
When you get to IP settings put in the following:
IP Address: 192.168.0.4
(Or whatever your Computer's LAN IP address would be.)
Subnet Mask: 255.255.255.0
Default Router: 192.168.0.4
Primary DNS: 8.8.8.8
Hit next on everything until you get to the end,
don't worry about doing a test, as it won't work for this.
Turn on the PKG Linker server,
you may have to try it twice, sometimes it fails when I first try it, but the second time always works.
Once the server has started, it's as simple as
putting your PKG files in the PKG Linker folder,
Generate a new list
Download the new list from the PS3's Package Manager
reset your PS3
Enable HAN again
Go to the server list
Download your PKG's
I hope this might help you try to set yourself up with a direct ethernet connection.
Setting it up like this, you should not have to change your IP settings anymore as long as you are connected to the same modem on your PC.
When you want to connect online (which is currently useless right now for gaming with HAN installed, as we can't update to 4.83 right now) you can just go back to internet settings on PS3
and set your connection up as normal automatically.
When you want to set the connection back up for PKG linker on your PS3,
just select Manual again on Internet Settings, it should still have your manual settings saved
and won't have to input them every time.
This is how I do it anyway.
It can be a bit of a hassle setting it up correctly the first time,
but it gets easier after that as you won't have to mess with
all of those network settings anymore.
