Need help with DHCP relay, trunking (possibly), and VLAN routing. Thanks!

Hey Guys!

This is my first time posting on this forum, but I'm sure it won't be my last.  I am very new to Dell switches and some of the complexeties of VLANs, trunking, DHCP relay, etc.  I know some basic stuff, but this project I'm on is testing my limits.  I'm going to learn more about Dell switches, but for now I need some serious help.

We have three buildings, I'll call them 1, 2, and 3, with about 50 computers in each.  They're tied together via cat6.  We want each building to have its own subnet based on the 192.168.x.x range.

The main building has a superscope set up of 192.168.0.1/22, a DHCP server at 192.168.0.51, and a WatchGuard firewall at 192.168.0.1.  On top of this, we have a Unifi wireless network as well in each of the buildings.  This was a flat network with the superscope spanning all buildings.

I have vlans set up for building 2 (VLAN20), and building 3 (VLAN30), but am leaving the building 1 in the default VLAN1 because I want to change as little of the existing building as I can.  If I need to put it in a VLAN (VLAN10), I certainly can and will but I don't want to change the addressing scheme for Building 1 as that's where all the servers are.

In each building I have a Dell N3048 and a Unifi router for PoE.  The Unifi network is on VLAN3 10.0.0.x and VLAN1000 10.10.10.x (not set up on the Dell switches).

With the below configs, I can't forward DHCP traffic to the sever in Building 1 on 192.168.0.51.  Also, PXE boot in the other buildings won't find the PXE server, which is also 192.168.0.51.

The Unifi wireless doesn't communicate across the VLANs either.

Any help would be GREATLY appreciated!

Thanks tremendously to everyone in advance who helps and sympathizes with my plight!

Very sincerely, Aaron.

p.s.  Please be kind with the configuration mess.  I'm out of my league on trunking (I don't even know if I need trunking) and such.

p.s.s.  I put DHCP on the switches because I couldn't get the relay going.  If I get the relay going (which I need for the PXE boot) I'll take DHCP off the switches.

BUILDING 1:
===========

!Current Configuration:
!System Description "Dell Networking N3048, 6.2.6.6, Linux 3.6.5-50bbccb7"
!System Software Version 6.2.6.6
!
configure
vlan 3,20,30,1000
exit
vlan 20
name "Building2"
exit
vlan 30
name "Building3"
exit
slot 1/0 3    ! Dell Networking N3048
stack
member 1 4    ! N3048
exit
ip name-server "192.168.0.51"
ip routing
interface vlan 1
ip address 192.168.0.19 255.255.252.0
exit
interface vlan 3
ip address 10.10.10.9 255.255.255.0
exit
interface vlan 20
ip address 192.168.20.1 255.255.255.0
ip helper-address 192.168.0.51 dhcp
exit
interface vlan 30
ip address 192.168.30.1 255.255.255.0
ip helper-address 192.168.0.51 dhcp
exit
interface vlan 1000
ip address 10.0.0.9 255.255.255.0
exit
ip route 0.0.0.0 0.0.0.0 192.168.0.1
username xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx
!
interface Gi1/0/42
switchport mode trunk
switchport access vlan 30
switchport trunk native vlan 30
exit
!
interface Gi1/0/44
switchport mode trunk
switchport general allowed vlan add 3,20,30,1000 tagged
switchport access vlan 20
switchport trunk native vlan 20
exit
!
interface Gi1/0/48
switchport mode trunk
exit
snmp-server engineid local 800002a20364006aead2e1
exit

BUILDING 2:
===========

!Current Configuration:
!System Description "Dell Networking N3048, 6.2.6.6, Linux 3.6.5-50bbccb7"
!System Software Version 6.2.6.6
!
configure
vlan 20
exit
slot 1/0 3    ! Dell Networking N3048
stack
member 1 4    ! N3048
exit
ip routing
service dhcp
ip dhcp excluded-address 192.168.20.1 192.168.20.50
ip dhcp excluded-address 192.168.20.200 192.168.20.254
ip dhcp pool "Building2"
dns-server 192.168.0.51 8.8.8.8 8.8.4.4
default-router 192.168.20.1
network 192.168.20.0 255.255.255.0
domain-name Beta.local
exit
interface vlan 1
ip address 192.168.20.2 255.255.255.0
exit
interface vlan 20
exit
username xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx
!
interface Gi1/0/47
switchport mode trunk
exit
!
interface Gi1/0/48
switchport mode trunk
switchport general allowed vlan add 20 tagged
exit
snmp-server engineid local 800002a20364006aead291
exit

BUILDING 3:
===========

!Current Configuration:
!System Description "Dell Networking N3048, 6.2.6.6, Linux 3.6.5-50bbccb7"
!System Software Version 6.2.6.6
!
configure
slot 1/0 3    ! Dell Networking N3048
stack
member 1 4    ! N3048
exit
service dhcp
ip dhcp excluded-address 192.168.30.1 192.168.30.50
ip dhcp excluded-address 192.168.30.200 192.168.30.254
ip dhcp pool "Building3"
dns-server 192.168.0.51 8.8.8.8 8.8.4.4
default-router 192.168.30.1
network 192.168.30.0 255.255.255.0
domain-name Beta.local
exit
interface vlan 1
ip address 192.168.30.2 255.255.255.0
exit
username xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx
line telnet
exec-timeout 120
exit
!
interface Gi1/0/47
switchport mode trunk
exit
!
interface Gi1/0/48
switchport mode trunk
exit
snmp-server engineid local 800002a20364006aead2dd
exit

Very sincere thanks!!

-Aaron