If you are aiming to go on to 5k training, then you need to keep pushing that LT. For the one mile, LT work is less important since you are going to be so far above it during races. Aiming for 5k, you want to be driving that LT up as high as possible in the next few weeks. (side note: you are a little bit behind here, my guys all began the work you are now doing in Sept ? mind you, they have some important races in May/June).
If you have been following what I advised, then for the last 10 days or so you should have been doing this:
1 x per week 8-10 miles continuous at 155-160 HR as part of a 90-100 min run.
1 x per week 3 x 10-15 mins at 160-165 HR with 2-3 mins jog recovery (again within a longish run).
For the next two weeks, let the HR on the second run ease up to 165-170 and this might be somewhere around 6.30m/m (for you).
Now I would make sure you get in some faster work. Introduce the 200/200s once per week. Aim to run around 38 secs (on) and 50-55 secs (off). Note here that it is the 200 float (recovery) that is the important bit. Any old fool can run 200s in 38 secs and stand around for 55 secs and go again. It is only if you can jog 200m in the 50-55 sec period can you be sure your aerobic system is starting to pull its weight. Build up to where you can run 25 laps continuous without being overly stressed. Note also here that 38 secs is around your 5k pace, so the transition to that kind of stride pattern in phase two will not feel awkward.
In the final 3 weeks of this base run:
1 x per week 2 x 30 mins (or 1 x 60 mins) at 160-165 HR
1 x per week 3 x 10-15 mins at 175-180
(in both of these, you are really looking to see that pace vs HR remains steady... that you do not have to slow down to maintain HR. If in doubt, obey HR).
1 x 200/200s
All else 145-155 HR (as your body feels)
In phase two you are going to move on to vVO2max work, and here I would refer you back to the very first post in this thread. You should schedule 1 x (or 1.5 times) per week for maintenance/improvement of LT. And 1.5 x (or 2 times) per week at 5k leading up to 3k paces. These can begin with sets of 400s at 5k pace with 100m jog recovery, and build up to 1200m repeats at 5k pace with 4 mins jog. Then move on to 3k paces... The rest of the week, easy aerobic for 45-90 mins (as required). Aim for around 6-8 weeks work in all.
The week can be 1 x LT and 2 x vVO2, or 1 x LT, 1 x vVO2 and 1 Mix)
Always be careful to protect what you have already got, and don't ever get into, or even close to, knee grabbing/sucking wind territory. I always schedule an "unloading week" every fourth week or so. Drop all intensity, even have a couple of days off, then get back into it with renewed enthusiasm the following week. Think long-term. You do this right, the results will come. Don't be a "star" like some youngsters who just twinkle for a little while and then go out. You cannot do it all in one year. Next year's base will be better, because you will come into it a higher level.
I personally would try the 500s taper for Nats. But I would monitor every session of every runner (and do them at the mile pace they are currently capable of, not some PR pace of next June). You know what effort level you are aiming for, so make sure that that is all they put in (there can be a temptation to boogie on these). If they need longer than 5 mins recovery, give them longer (although if the pace is right, they should be recovered by then... although that depends a lot on their aerobic background). If you are unsure of one mile pace, ease it up to 3k pace. You really cannot do much harm with such low volume.
I was first told of these in the early 90s by a Russian physiologist I came to know very well. I also saw them mentioned later in a book written by a guy from South Africa (Norrie Williamson??) I was lent this book by a friend who also loaned me Noakes' book. I have never read Anderson's newsletter, although I have seen some of his stuff on pponline and remember him from way back with RW.